The Excavatrix

Our Blog is moving!

2011-12-11T13:51:00.000-08:00

Hello fellow fossil enthusiasts and asphalt-saturated bone from the Ice Age lovers. The Excavatrix as you know it today will no longer be the site for our updates. To check out what's new with fossil digging and processing here at the Tar Pits, please refer to our brand new tarpits.org website (Yay!) that's launching tomorrow, 12/12. The new "Blog" can be found by clicking "Blog" at the far right of the website's top page menu.

The Excavatrix at blogger.com will still be available to view old posts at this time.

I'd like to give a shout out to Andie, the awesome creator of The Excavatrix at blogger.com and hope that you all will enjoy the new tarpits.org website!

We opened another box!

2011-08-20T10:25:00.000-07:00

This is box 12. It contains the next deposit from Project 23 to be excavated.

Deposit 12 facts:

10,000 pounds (pretty small compared to the others)
Sits at north-east side of compound, front row along the north fence
Excavators will be able to stand or sit at its sides
No indication in notes as to what it may contain
associated with 6 spoils buckets

Under the white tarp, the deposit is seen wrapped in plastic with supportive foam and fill cushioning its sides

Brain foam, Ew!

It will be an ex-home to mud daubers

and paper wasps

We cleared away the plastic and scanned the surface for fossils

This is it from the box so far, some very weathered large bone frags:

Before setting grid lines, we need to consider that the box's current orientation to north is different from its original orientation

Measurements written on the side of the box indicate its orientation from north as it was in the ground. The box north line is determined from these measurements.

The top board is cut down from one side and it's ready for digging

Karin found the 6 deposit 12 buckets from the shed and so far they have been more interesting than the box, containing bones from various large mammals

This is a sabertoothed cat tibia that had been broken in three pieces

The bone is lighter in color and more brittle than our normal asphalt protected bones

And upon closer inspection we see crystals growing on the cancellous tissue

Also, a horse tooth!

There are also fragments from other very large animals. I don't know which sides of the deposit they all came from, we will have to see as we go through the box, hopefully, maybe, where the rest of that cat, horse, and others are!

How to Screen Wash Project 23 Matrix

2011-06-01T09:45:00.000-07:00

Over 2000 buckets of matrix produced from Project 23 thus far and what to do with them? Reduce! Our matrix contains a lot of non-asphaltic sediment that can be washed away. Over past months Excavators have been working on a new system for screen washing, with major organizing and tool/equipment building done by Karin.

First, we choose buckets that have a lot of fine non-asphaltic sediment and soak overnight:

We then scoop muddy squishy matrix from its bucket into a specialized bucket with a 20 mesh (size used for micro-fossil sorting) screen on the bottom (that Karin made) and swish and break

down the fine dirt that washes into tubs of water (that Karin made, sitting on a wooden platform that Karin made)

Between washings, the bottom is cleaned. It is a rather enjoyable process bringing us back

back to our mud pie making days.

The matrix dries on screens and then is bagged. Sometimes visible microfossils are "high graded" into a capsule within the bag. One rather large recent surprise was a Nothrotheriops shastensis patella in matrix from Box 1. It's the first Shasta ground sloth found in Project 23!

A five gallon size bucket of matrix reduces down to about a gallon size bag of matrix that will later be degreased, and then we re-use buckets - yay!

In other P23 news....

Box 14 had a bit of a make-over with our use of one of the fancy canopies from Media Day

Little Timmy's left lower mandible shows up near a disturbed part of the deposit

An herbivore (probably bison) maxilla is revealed in Box 1

And in the lab, Herb found two elements (occipital horns and maxilla) from a coastal horned lizard in Box 14 while sorting matrix from a block of asphaltic sand containing many small delicate bones. These are the first horned lizard bones found since 1929 in Pit A, and only the second individual ever identified at Rancho La Brea.

Cleaning and the Media

2011-03-27T13:30:00.000-07:00

Spring cleaning started early this year with Pit 91 glopping and maintenance.

Since it is a dirty job, Laura donned our recently donated fishing waders/frog suit

Michelle did some reverse basting to remove water sitting

around the fossils.

Here Karin gets those tough to reach support beams with

her vacuum hose extender handle to suck up the dirt

and leaves that Michelle bravely swept to the edge.

Michelle showcases our new Pit 91 decorations

And here's an ancient grid number I found on the wall!

Our even bigger excitement than cleaning Pit 91 in March was Media Day.

We prepared the compound and Box 1 and 14 for numerous visitors. Both

large fossil deposits from these boxeswere well exposed and shined and the

reporters were given direction on where to stand.

Along with showcasing the boxes, we also had a table of fossils in the compound

including an unprepared large tree branch, some prepared Little Timmy elements

and 6 prepared saber-toothed kitten radii.

photo by Nola Milner

In the lab a table was set up to show off Clyde's skull and mandible, juvenile bison from Box 7B, saber-toothed kitten mandibles and maxillae, elements of Fluffy, Donatello, oak leaves, beetle eaten pine, and millipede.

The fishbowl lab showed off the recently opened skull of Zed and here's the

Project 23 crew standing around him at the end of the day

John and Shelley gave a speech to numerous reporters about what has been

discovered in Project 23 for the last two years and then the reporters were

released to the table, boxes, and lab to interview us.

photo by Nola Milner

Here are some links to articles as a result:

LA Times (Blog): h ttp://latimesblogs.latimes.com/unleashed/2011/03/la-brea-tar-pits.html

La Opinion (Print): http://www.impre.com/laopinion/noticias/la-california/2011/3/10/mamut-cuenta-la-historia-de-la-244025-1.html#commentsBlock

Trekaroo (Web): http://blog.trekaroo.com/2011/03/14/monday-madness-win-a-family-four-pack-of-tickets-for-the-page-museumla-brea-tarpits/

URCA (Radio): http://www.yourcaliforniashow.com/radio-links/prehistoricbonesnearlosangeles-homebrewing101-andmuchmore

LA Weekly (Web): http://blogs.laweekly.com/informer/2011/03/la_brea_tar_pits_new_fossils.php

KPFK (Radio): www.hearinthecity.org

Plus, close to 300 media outlets ran the AP story from when we were interviewed two days before Media Day

http://www.npr.org/templates/story/story.php?storyId=134384948

Here are the excavators looking our best on Media Day.

photo by Nola Milner

Continuing on with cleaning, last week we poked through the collection of animal skeletons that are in various states of decay in the "monkey shed." With eagerness and sometimes slight reluctance, Michelle took an inventory to show her forensic anthropology classmates who might assist in preparing them for storage in our modern comparative collection in the lab.

Karin found a shy new friend

And another....the bear labelled "Bozo"

and an apparently to Michelle, an absurd pelican beak

The fun never stops here, even with the recent torrential rain.

During lunchtime the canopy over deposit 14 collapsed from the weight of water

We also brought out the warm and cozy Tyvec suits that Bruce donated

And if you need a fossil fix (aside from looking at our great work in pictures taken by the media), here's a broken bison rib in box 14 currently exposed. At the top left there is a bison sacrum.

And check out our new scaffolding next to Box 1, complete with canopy!

We are ready for spring/summer digging!

New Staff Lounge

2011-01-31T15:05:00.000-08:00

This was Box 7A in 2009:

Now it is these roughly 600 buckets lining the interior fence:

The floor and wall boards were cleaned up, many of them saved, and now we have a nice new staff lounge:

Here's one of the 7A board lurkers:

Now that 7A is done we are spending more time on Box 1 again. Christina and Laura

found a dire wolf baculum!

We are also working on exposing more of the large bone deposits in boxes 1 and 14 and making them pretty to show off on our upcoming media day.

In a certain area of box 14 I have been finding a few bones with a colorful oil film.

I don't recall having encountered this before in my Project 23 digging experience.

Winter Update

2010-12-29T13:38:00.000-08:00

It has been cold. And rainy. But this has not stopped us from accomplishing a lot both outside and inside.

Current matters of the digging kind:

1. Box 7A is almost done!

and volunteer Katlynn Thompson makes excavating the rest of it look easy

2. Box 14 has been exposed down to more levels.

After removing more fill and plastic we have exposed more of the deposit edges and found more boards, metal bands, crumbling sides, buried artifacts from initial excavation (electrical wiring and a tupper-ware lid) and discovered this:

??? A hole in the west side edge of the deposit.

Recent finds of the ancient kind in 14 include:

Dire wolf sacrum found at bottom of level 3

Little Timmy's humeri. Here is the proximal end of one standing exposed. It has an old break that caliche filled. This end was removed at that break and the rest of the bone lies in level 4. We also have its other humerus lying to the west in L4.

A coyote skull, seen under the dark hard asphalt in this picture.

It's molars are in the lower center.

We continue to be captivated in curiosity by box 14 caliche. This is the top of a layer of it that we exposed in grid D-3 L4.

Here is a cross-section of caliche in the D-3 L4 south wall.

And a closer look because we love it so much.

Recent excavator activities of the non-digging kind

Last month excavators and Aisling took some time to make 2 new temporary museum exhibits featuring findings from Project 23. After putting some good use to the many cold rainy days of December, we now have an exhibit about the taphonomy of our box 1 American lion "Fluffy" and an exhibit about how box 5B was excavated and what we found. Come check them out in the Page Museum near the "fishbowl"!

Also, we have been starting to screen-wash non-asphaltic matrix buckets from box 5B to see if they are sterile. Here Michelle and Karin break apart matrix of different soil types within a grid that have been soaking in water.

We are planning on having a larger washing station made for us so we can quickly sort through

the buckets

Stay warm!

Trevor's Lab Update and words on National Fossil Day

2010-10-20T15:32:00.000-07:00

Updates!

2010-10-19T12:18:00.000-07:00

It has been eventful times this fall. Aside from uncovering hundreds of new fossils we've been involved in a couple other fun activities like speaking to volunteer Mary Simun's AP Environmental Studies class and having a table at NHM's Haunted Museum where we educated on the 3 sloths found at RLB

Also, there have been some major staffing changes. We celebrated Chris Shaw's retirement and are also now fully staffed (except for Collections Manager) Karin Rice and Laura are now full-time, and Christina Lutz is part-time. Congrats to all!

Now for some needed box updates!

I know that some are wondering what has been up with box 1, and that is...a bit of remodeling, pedestaling, and power digging. Box 1 currently has some of the most curious and hardest grids to excavate which has lead us to take slightly different approaches to traditional digging. We are now "pedestaling" around the main fossil deposit in the south end. This means taking the matrix around the bones down to deeper grid levels without removing the bones. This creates a side view of how they are in place which helps us see how the deposit formed. To easier accomplish that excavation approach a "window" was removed from the south wall next to the bones so that someone can stand outside the box and excavate from the side as Tara demonstrates here, working across from Michelle.

The rest of the open grids in box 1 are sterile and difficult which means its time to bring out the power tools if we want to get this box done in the next 10 years. Michelle and I have been using the pneumatic hammer and Herb brought in his electric hammer which proved very useful in clearing out half of a grid in one day. Here's Michelle digging her "hole to China" in a hard sterile grid next to the bone deposit.

And 7A?

Since 7A was re-opened on the 7th of July all of the "C" grids from level 3 to the bottom boards have been completed (roughly 4 tons of matrix) and now we are well into the B grids

The major fossil finds are 3 horse cervical vertebrae. Other bones have been sparse - just a few bones from smaller animals and random worn large bone frags. There are however gastropods galore

And some neat geology has been revealed, such as this wavy silt/clay structure that was probably created by asphalt deforming soft sediment

Volunteers have been great at chiseling though the tough old asphaltic stream beds of 7A.

Everyone still loves the safety glasses which are a necessity in 7A...but will they protect Karin from Justin's apparent backstabbing...?

With their help, including the "Master Chiseler" Jack (aka The Chiserater, Jack the Chipper, or The Grand Chizier) who competes with Herb as to who can produce the most buckets in a day, we will probably have this box finished within the next couple of months.

And there's continual awesomeness in the large box 14 deposit:

I like to call it a fossil buffet

Here's a closer look at the dire wolf skull that was "biting" our box 14 juvenile mastodon's scapula

Both of Little Timmy's scapulae and a humerus have been exposed. Plus...we found the back of a sloth skull! And recently a coracoid from a teratorn, the largest bird found at RLB - its a giant condor with a wingspan of 12 feet!

Box 14 also has this

See those bluish-gray bands that surround the brown bone? That is a caliche that has never been seen at RLB before and its formation is still somewhat of a mystery...speaking of which...did anybody catch the Page Museum featured in the Travel Channel's "Mysteries at the Museum" show that aired last week?

an overdue farewell

2010-10-14T20:45:00.000-07:00

Hey asphaltophiles,

This is old news to some of you, and of no consequence to others, BUT:

As you may or may not have noticed, I (Andie) have not been posting to this little blog. And that's because I am no longer an excavatrix! About two months ago I packed up my 18-year-old Honda and drove to the lovely twin cities of Champaign-Urbana, Illinois. I am in grad school for library and information science, with a specialization in data curation! It's super duper fascinating, I promise.

Carrie, senior excavatrix extraordinaire (and maybe others) has and will continue to update the blog, time permitting. Seeing as she is fully awesome, the blog under her guidance has been (and will be!) fully awesome as well.

So please, wish me luck in the soon-to-be-frozen north as my Californian blood is frozen solid this winter and my brain is filled with way too much information about information. And best of luck to all the diggers, present and future, of La Brea: may your trowels find tapirs, and your discovery marks be few.

Cheers,
Andie

The Great Volunteer Bucket Moving Day

2010-09-26T11:04:00.000-07:00

On September 21, for about 2 hours, the Page Museum was graced with 100 UCLA freshman's extra pairs of hands as part of their Volunteer Day event, in which more than 4500 freshmen are involved in city-wide community service. When we were approached by them for work we thought it to be a great opportunity to get some needed gardening, painting, and matrix bucket moving done.

Project 23 was given 30 of the volunteers and a few of their captains to help us organize our buckets by concentrating buckets from each box to one location and ordering by grid, with each specific grid bucket being counted. Since having that many people in the compound at one time is a bit terrifying they were divided into 5 groups for each deposit with each group being supervised by a staff member (Michelle, Laura, and I) or volunteer (Karin and Christina) Taking time out from supervising the new garden addition, Aisling captured our bucket moving moments.

Here Laura explains to her freshmen how exactly they will be moving buckets onto the fancy platforms that we constructed to protect bucket bottoms from rusting.

The volunteers were very enthusiastic to help move buckets for science

The driveway was utilized to pre-sort buckets for box 1 and 5b.

There were a lot of buckets to move and sort! We could have used the students all day because the two hours of time was not enough. The job was finished by myself and others including Trevor, Herb, Christina, Jean, Jack, Jenna, and Justin during 2 days following. It was a lot of work but the students were super helpful in doing the majority of the moving and now gathering data about each deposit and processing matrix will be much easier.

We now have the more convenient ability to know exactly how many buckets have been produced from each box and each grid. Here's some results:

Number of buckets per completed box:
Box 5b - 541
Box 7B - 267
Box 10A - 191
Box 10B - 91

For boxes still in progress:
Box 1 - 428
Box 7a - 279
Box 14 - 71

This gives a grand total of 1868 buckets produced in the past 2 years, 1724 of which were moved that day. That is an average of 74720 pounds (37 tons) of matrix that has been excavated out of Project 23 over the past 2 years. With 19 boxes left to finish that could mean about 100 more tons of matrix left to go.

Many thanks to all of those involved!

Introducing Box 14

2010-08-15T08:13:00.000-07:00

Excavation of deposit 14 has been underway for almost 2 months now and has been very fruitful, as expected, due to what we have already seen in the amount of spill-over fossils that were put in buckets when the deposit was removed from the ground, as demonstrated here by Andie in a previous blog. But before we could poke our dental picks in the top asphaltic sugar sand already showing signs of large bone we had to transform the highly awkward box into something we could work with.

This is how it came to us, after protective tarp removed

The actual deposit is the darker colored sediment in the center. It fell apart when they were trying to excavate it and came to us wrapped with a few boards and metal bands, then plastic, and then supported by tons of the sterile "fill" dirt within the space of the tall box.

Box excavation preparation included cutting the metal bands that crossed over the top of the box, assembling scaffolding, removing front top board so the public can see us work, affixing handrails for easier boarding, setting up a shade canopy, and determining grid lines, and then box 14 was ready for digging!

The fossiliferous asphaltic sugar sand midsection of the deposit is relatively easy to dig in. It softly peels and crumbles away from the bone. We never have it completely easy though, as within it there are also spots of hard oxidized asphalt as well as bones that have already been fractured. Given that the deposit was disturbed upon excavation we also have not been taking three point orientation measurements of bones as they are believed to be disrupted from their original position. The only data thus far taken has been the grid and level that the fossil is found in.

Included in what we have found so far:

2 large hervibore vertebrae including sloth

1 coyote skull

1 dire wolf skull, tibia, radius

2 juvenile saber-toothed cat mandibles

lots of bird - including golden eagle skull, teratorn sized limb bones, male
turkey, and hawk

"lots of turtle" - according to Trevor there are at least 3 individuals

pieces of juvenile mastodon skull including a maxilla with teeth that
indicate its young age, possibly younger than any mastodon in the RLB
collection, along with a tibia

Meet "Snuffleupagus" or "Dumbo"

field photo

after some cleaning by Henry

Also, here's an example of what the main fossil deposit in 14 looks like

and the bird beak I found (my first), which is eagle sized

and the perfect furcula from a medium sized hawk that Michelle found

Deposit 14 has been worked down two levels and in order to continue we
have started removing fill dirt so that we can remain excavating from the deposit's side. Last week bucket by bucket we removed over a ton of fill. Literally. Thank you Sunday volunteers Karin Rice, Bruce Fischer, and Katelynn Simpson for being awesome dirt movers!

Now this is 14's current look

In other P23 news the reopening of the rather non-fossiliferous deposit 7a has yielded 3 horse cervical vertebrae and progress has been excellent in box 1. More updates are to come!!!

Farewell to Deposit 5b

2010-07-14T16:23:00.000-07:00

Box 5b is done. We started in early November, and after 8 months there is now an empty spot in front of box 14. The "June gloom" weather during the last days of 5b matched the sadness we felt in knowing that the excitement of 5b would soon be gone. We had a good time discovering its intriguing asphalt infused stratigraphy and cool fossils including:

Clyde, the partially articulated camel
Alphie, the juvenile mammoth
Little Timmy the juvenile coyote
Pepe the weasle
and a yet to be named rattlesnake.

The last noticeable fossils in 5b were freshwater snails and plant in asphaltic sediment and the bottom layer consisted of virtually sterile partially asphalt infused greenish gray clay.

Here Laura works with volunteers Cheyenne Robinson and Pat and Mary Simun to extract the last remains of fossils at this level

Michelle joined them for a time out to capture the adoration for our special safety glasses

Volunteer Herb Schiff hammers through the final remains

And then there was none.

Depending on who you ask one highlight of finishing a box is discovering who has been living underneath it. As the final bottom boards were lifted there was an unveiling of slugs, crickets, brown widows, black widows, and some other unidentifiable by me spiders and insects.

Well hello!

Box 14, the large box situated behind 5b and next to box 1 is the next to be opened. It is a partially slumped deposit which means complete measurement of fossils will be limited to what we know is for sure in situ. The idea is to quickly work through the thousands of fossils we will find slumped in the easier to excavate asphaltic "sugar sands" and the area it sits will then be used for bucket storage.

We also look forward to meeting the other half of 5 on the other side of the compound someday hopefully soon to learn more about deposit 5 geology and see if we can find more of Clyde and Alphie.

camelops!

2010-06-06T15:08:00.000-07:00

When we last left our heroes:

They were digging away at deposit 5B. And the still are! The deposit has shrunk considerably from its original size, but excavators are still looking for more elements of Clyde, our partially articulated, partially complete Camelops hesternus.

As you may remember from two posts ago, we had most recently exposed his almost perfectly articulated 7th cervical and first thoracic vertebrae, and were pleased to find that his 6th cervical vertebra wasn't too far off:

Here's a closer look; volunteer Henry is holding a clean Camelops hesternus 6th cervical vertebra from our collection for comparison.

1) neural spine -- 2) postzygapophyses -- 3) prezygopophyses -- 4) henry

We have no idea why the 7th cervical and 1st thoracic verts stayed articulated over 10-40k years, while the 6th cervical wandered off a foot and a half to the north. However, we do know that this brings our tally of camel bones from deposit 5b to:

-1 skull

-1 jaw

- 8 thoracic vertebrae

-2 cervical vertebrae

- 1 right humerus

- assorted rib fragments

- 1 camel toe

- and maybe a femur, but we're not sure on that yet

project 23 on 'best of la'

2010-04-25T22:28:00.000-07:00

Hey, we're on tv! Again! Video below features Dr. John Harris & Trevor Valle speaking, and Carrie Howard, Meena Madan, and Tara Thara excavating (and Aisling Farrell and myself for approx 2 seconds a piece, which is perfectly a-ok, because being on tv is scary). "Best of LA," check it out (email subscribers -- I think you'll have to click through to actual blog to view, sorry):

EDIT: UGH embed does not seem to be working. Here is link: http://bestoflatv.com/view/1185

why working in a public park is fun.

2010-04-24T17:21:00.000-07:00

Little kid questions of the week (both addressed to Carrie):

Small child: "Do you guys ever find anything besides bones in there?"
Carrie: "Like what?"
Small child: "Like weapons??"

I'm sure the kid meant spearheads, but my mind went instantly to a giant ground sloth holding a rifle.

Small child: "Why do they save all the dirt?"
Carrie: "We will look through it for microfossils."
Small child: "Microfossils... ohhhh like ancient germs??"

Now that one, I suppose, depends on what you consider a germ... We do get asphalt-eating bacteria, after all...

One of the most frequent questions we get from park visitors is, "what do you do when it rains?"

clearly, you SMILE ADORABLY like laura

Well, as we've had to do more than once recently, we.... go inside. Despite our dirt-covered faces and tar-stained jeans, we are CIVILIZED after all (although to be fair, if it's only raining a little, and we've got a decent tarp rigged up, at least half the staff will opt to stay outdoors: "it smells nice!").

But this is California: we don't really have weather.

this photo was taken in february; they're smiling because it's 80 degrees out. sorry, everywhere else.

People also ask which is better: digging in the cold, or digging in the heat. After several years of excavatrix-ing, I've become quite the connoisseur of digging conditions. Colder days have their advantages -- the asphalt "freezes" to the point that it chips off in these nice ovoid fragments -- conchoidal fractures, as in flint -- and you can get rid of big chunks of sterile dirt at one time.

And sometimes you find neat stuff in between the fractured pieces:

imprint of an insect wing, photo by the awesome carrie howard

SO MANY MILLIPEDES........

However, cold days mean no detail work -- no dental picking! Which means no working on awesome stuff like these two articulated camel vertebrae (still from Clyde, our camel in 5B):

Cold days, for me, also mean I'm at least 83% more likely to hit my left thumb with my own hammer before 9:30am. But I'm weird.

Warmer days, like I said, mean detail work:

i'm not sure what insect or which part this is, but it's neat

more amazing photos by Carrie

Termite gnaw marks from the Pleistocene -- very cool. The keen-eyed excavator that got them out intact -- possibly cooler (I bet it was Carrie -- apparently this is We Love Carrie week).

So, warm days = melty asphalt and pretty fossils. However, warm days eventually turn into hot days, which eventually turn into oh-my-god-i'm-dying-get-me-an-iced-tea. We've got another 2 months until then, though.

Another keen-eyed excavator (your truly, to tell the truth) spotted a new instance of the family Suidae at Rancho La Brea....

yes, it's a pot-bellied pig. no, it's not george clooney's. damn.

but, alas, not exactly Pleistocene in age...

Monarchs at Pit 91

2010-02-24T13:57:00.000-08:00

Volunteer Anna Lopez planted milkweed adjacent to the Pit 91 viewing station to entice monarch butterflies. It has been fascinating and refreshing for us to observe the life cycle of animals that are not dead:

we're back!

2010-02-21T10:31:00.000-08:00

Friends, I am torn, because on the one hand, I feel extremely bad for not posting for two months, but on the other hand, it is because we have been busy being amazingly productive paleontologists who do not have time for this new-fangled computer contraption -- we simply have too much dirt, too many bones, too much science. Am I to apologize for progress? I think not. But am I to apologize for poor journalism? Absolutely.

As penance, I humbly offer you easily enough material for three separate posts. Photo heavy, be warned.

From New Year, New Dirt

This, as you may or may not remember (it has been a long time, after all) is a rough map of the Project 23 compound (Pit 91 is the square to the south). We've finished 3 boxes (10A, 10B, and 7B, all x'd out), got half-way through another (7A, put on hold until we can better figure out what to do with it), and are still digging away in deposit 1. Deposit 5B is newly opened. 14 is currently slated to go next. For a better sense of scale, here's a photo of the compound from a couple months ago:

From New Year, New Dirt

And here's a photo from shortly thereafter:

From New Year, New Dirt

Woah! What happened to 5B??? Well I will tell you.

From New Year, New Dirt

We took the sides off! Deposit 5B's box had warped somewhat treacherously from the get-go; its base was damaged in the move from LACMA to here. Rather than working around unweildy boards, we decided to experiment and take all the sides off at once. We hoped this would allow us to get a look at the deposit's stratigraphy straight away, so we can better anticipate where fossils will and will not be. We also hoped that the deposit wouldn't immediately fall apart...

Jack is so proud! From New Year, New Dirt

As you can see in the photo above, we were fortunately (mostly) right on both counts: after removing all the boards, we were greeted by some really neat looking strata, and the block remained largely intact....

Pat Simun wins MVV (most valuable volunteer) From New Year, New Dirt

...after removing some of the looser chunks of earth. If we do this sort of thing again, I think we'll only remove the top half of the wooden crate. That way we'll still see the layers, but with some extra stability.

If only lasers actually worked this well. From New Year, New Dirt

As in other deposits we divided this one up into grids, and are excavating one grid "column" at a time, and creating detailed stratigraphic drawings and lots of photos as we go.

So, as I said, one of the benefits of this excavation method is that we are getting a much better idea of the deposit's geology than we otherwise would, because we're looking at so much of it at one time. The contact between the asphalt and the surrounding silts and clays is much more defined than we've seen in the other deposits from Project 23.

From New Year, New Dirt

And as excavation has progressed, we've found that there are some truly unique and interesting things about this deposit:

1) there are two very distinct layers of asphalt within 5B-- likely from two different venting/entrapment episodes, and possibly thousands of years apart from one another... or maybe only 10 -- we won't know until we start carbon dating things. You can hopefully see them in the photo below -- one near the top surface of the deposit, and on near the bottom.

2) there is a partially articulated CAMEL (Camelops hesternus) skeleton in the top layer! This is huge -- camels are fairly rare in our collections, and articulated skeletons are rarer still.

From New Year, New Dirt

So far we've recovered its humerus:

From New Year, New Dirt

its lower jaw and skull:

From New Year, New Dirt

and about 6-7 thoracic vertebrae:

Kristen's forearms are awesomely recognizable. From New Year, New Dirt

That's the camel's skull up top, and a line of four thoracic verts below. Very exciting.

Meanwhile, in deposit 1, we are still digging away:

From New Year, New Dirt

As I think I've mentioned before, there are several grids worth of broken bones in very hard sediment -- the dirt is harder than the fossils. It's difficult, slow work. We've started taking them out of large bone masses like this:

From New Year, New Dirt

Awful looking, right? However, the strategic breaks made while taking the bone mass out of the ground SHOULD be easier to repair than the accidental ones made while trying to take each individual bone fragment out.

That having been said, after the block has been run through our brand new degreaser...

From New Year, New Dirt

The bones come out looking great. This particular chunk had three dire wolf metapodials in it -- perhaps all from the same wolf paw:

From New Year, New Dirt

Note how little of that matrix is made up of actual dirt -- by and large it's plant and bone material. We're still working the kinks out of our degreasing system: figuring out how best to operate it, how many people we need to run it, how best to sort through the resulting thousands of microfossils...

Well, I suppose that's better than a fork... From New Year, New Dirt

It's frankly overwhelming. We degreased a bucket of bones from the original APRMI salvage of the LACMA parking lot -- it was about 1/4 of the way full, and labeled "spoils" (i.e. not in situ, from pulled out of the ground by a tractor and left off to the side). The results:

From New Year, New Dirt

Thousands of bones. In one 1/4 filled bucket. Eagle beaks, rodent teeth, a bird synsacrum...

From New Year, New Dirt

a complete and perfect weasel dentary...

From New Year, New Dirt

several dozen assorted rabbit, rodent, and bird elements...

From New Year, New Dirt

tarsometatarsi from at least 4 different species of birds...

From New Year, New Dirt

and last but not least a lizard jaw.

And that's just 1 out of 327 spoils buckets, not to mention the who-knows-how-many-hundred matrix buckets scattered throughout the compound...

From New Year, New Dirt

Long story short: there's a lot of work to be done.

So, speaking of working: in the hopes of revitalizing this poor ignored blog, I'm thinking future posts will be faaaar shorter -- like, one photo and a paragraph -- but hopefully far more frequent. That way, you get more posts, and I can spend my Sundays doing Important Weekend Things like cleaning the tar out from my fingernails, getting the tar out from my laundry, and rollerblading (all at the same time? perhaps!), rather than writing about work when I'm not... actually... at... work. Not that I don't love the tar ranch! I just also love Venice Beach.

update: more sabertoothed cats and kittens

2009-11-16T09:47:00.000-08:00

Solar flares over our pulley. From Back in Dep 1

As I reported last post, we've moved back into the big box: Deposit 1!! And look how excited everyone is:

Volunteers Christina Lutz and Tara Thara. From Back in Dep 1

Those are the smiles of happy fossil finders. Why? Because they're actually finding fossils again! Between mostly planty deposit 7A, and really hard and sterile parts of deposit 1, we're been spending entirely too much time digging up dirt rather than fossils. Dirt = not fun. Fossils = awesome. It's very simple.

I've posted many, many pictures of this bone bed before (it's where we found our North American Lion skull and assorted long bones). And it's once again producing some really great feline finds:

Sabertoothed cat skull! From Back in Dep 1

The big dusty skull-looking thing on the bottom is a... big, dusty sabertoothed cat skull, with a complete sabertoothed cat pelvis immediately above it. And look a little above the skull and to the right:

Smilodon saber in situ. From Back in Dep 1

It's a complete sabertoothed cat saber!

Smilodon saber in one piece! From Back in Dep 1

And in the grid directly across from this one, we found 2 more sabertoothed cat kitten sabers:

Volunteer Steven Wintergerst holding a Smilodon kitten saber
From Back in Dep 1

This may bring our (estimated) minimum number of sabertoothed cats in this deposit to around 7: 3-4 juveniles, 1 sub-adult (teenager) and at least 2 adults (I will have to double check these number with the lab). It's actually possible to match sabers to skulls, by taking casts of the alveolus (tooth socket) and comparing the cast to the tooth! This is something we might want to do in the distant future; because this deposit is so small we may be better able to discern which bones belong to which individual cat -- especially for these 4 "kittens" we've found. Yes, they're all young, but they're not of the exact same age (which makes me think this isn't a singular litter that got stuck). So by determining the age of each young sabertoothed cat bone we find, we can figure out whose limbs are whose, and then perhaps extrapolate from that how much the asphalt has moved/disturbed the skeletons since they first got stuck 10-40 thousand years ago.

In non-mammalian news:

Turtle shell! From Back in Dep 1

2 partial turtle shells have come out of the formerly sterile areas west of the main bone deposit. Turtle shells are made out of a number of interlocking plates, and while the individual plates are extremely common, articulated/associated ones are not -- in fact, these may be the only even semi-complete shells we've ever found at Rancho La Brea. Trevor's been working on them in the lab, and has one of them somewhat reconstructed (which he will hopefully tell you all about at some later date if he ever gets around to making a blog post, hint hint).

FINALLY two other items of business:

1) This is Carrie!

New excavator Carrie Howard! From Back in Dep 1

She works here now! She likes rocks and photography and is generally great.

2) I don't often share links on here, but for those who are interested in science education in America and the general fight to keep evolutionary biology from being grievously misunderstood may find http://www.dontdissdarwin.com/ helpful.

Next post: so, what's in that barn-looking building next to the trailer?

Greg A. hunts for lunch by Pit 10 From Back in Dep 1

No, it is not dinosaur! It is a degreaser, which is far more useful and hopefully far less dangerous! More later.

update: out of 7A, back in to deposit 1

2009-10-17T16:23:00.000-07:00

they escaped from the tar pits, but not from each other: these two dragonflies were
found flying around together, attached at the hip by asphalt. Michelle kindly helped
free them. From 7A and back into 1

Right. So we've been working steadily in deposit 7A, and are about 1/2 a meter down in all areas. There were three bones immediately visible on the surface (all sliced by the tractor that found them, and horribly dried out), but other than that we've yet to find any substantial vertebrate fossil deposit. We've found a few scattered pieces of turtle shell (not to mention some extremely odd fragments of mineralized bone -- very rare for Rancho la Brea!) but none of the big jumbly bone masses we've come to know and love. What we have found:

Shells shells shells! From 7A and back into 1

Gastropods! And lots of them.

excavator hand for scale, From 7A and back into 1

These freshwater snail shells are further contextualized by the immense amount of plant material we've been getting out of the deposit as well; the northeastern corner of the deposit is filled with what appear to be tree branches (but possibly roots). Additionally, there's some interesting stratigraphy going on in this deposit: layers of river sand and large rounded rocks.

But as of yet no big vertebrate fossils. Boo.

For that reason (and because we're acutely aware we're already one year into a five year project!), we've put deposit 7A on hold, and re-doubled our efforts in deposit 1 (the big box we first started in).

That's usin' your head, Russ. From 7A and back into 1

And we've made some really impressive progress! But more on that next post. Until then, I leave you with this month's "What is it?" Check out the photo below, and leave a comment with your guess of species and element! Correct guesses win a congratulatory shout out on the next post, and the knowledge that they have bettered their internet peers!

I'll give you a hint: it's a fossil. From What is it?

Happy guessing!

what we did over our summer vacation:

2009-10-01T15:57:00.000-07:00

The scarab beetle in our compost pile says hello
From End of 7B, Beginning of 7A

Well, not a vacation from digging -- just a vacation from blogging. Apologies to all, and regular updates will commence henceforth. SO:

Nola hammers the lid on the last matrix bucket from deposit 7B
From End of 7B, Beginning of 7A

We finished excavating deposit 7B in early August. Final tally of things found is still pending, but all in all, it was rather pleasantly fossiliferous. Some of the cooler finds include a number of potentially associated bison bones (the bison itself has been named James K. Polk), a mostly complete sabertoothed cat skull (named Bixby) (I will have to explain our naming conventions in a later post...), several unusually large sabertoothed cat limb bones that might belong to Bixby, several rattlesnake vertebrae, a gopher skull, the usual slew of dire wolf bones, and lots and lots of tree branches (tentatively ID'd as manzanita). And nicely enough, 7B continued to produce bones down to its final few layers:

Sabertoothed cat cervical vertebra
From End of 7B, Beginning of 7A

This sabertoothed cat vertebra was found at the very bottom of the deposit. As you can see, the right-hand side of the vert was sheared off in the process of putting a bottom on the box -- no good! Ah well -- such is paleo-salvage. Of the 327 buckets recovered from the LACMA site, a substantial number were labeled "Deposit 7." Someday (hopefully sooner rather than later), we will degrease the buckets and try to find this vertebra's missing half, but for now, we best be moving on...

Deposit 7A
From End of 7B, Beginning of 7A

...to deposit 7A! 7A's a bit bigger than 7B, so we built this nifty railing to keep us from plummeting to our deaths (or, more likely, tumbling to a sprained ankle, but whatever, SAFETY FIRST dang it), and we've got some strategically placed Little Giant ladders around to help us in and out. But check out that silver thing on the side:

it's like a slide for matrix! wheee!
From End of 7B, Beginning of 7A

Rather than breaking our backs hauling buckets in and out of the box, Michelle came up with the great idea of leaving the buckets on the ground, and using a make-shift funnel to pour the matrix in. GENIUS! And I can't believe we didn't think of it earlier. It's not about working harder -- it's about working smarter.

After finding deposit 7B fossiliferous to the very end, we had high hopes for 7A, but were (understandably, I think) a bit disappointed to find only this dehydrated mess greeting us on the deposit's surface:

that chalky stuff in the center is bone. ugh.
From End of 7B, Beginning of 7A

Blech. Nevertheless, we soldier on! We've been working on Deposit 7A for about 2 months now, and we have found a few specimens, here and there...

Laura finds a specimen here, a specimen there...
From End of 7B, Beginning of 7A

...but more on that next post, which I promise will be next week (I don't want to overwhelm you after my long absence). Cheers!

Boo!

2009-09-04T01:49:00.000-07:00

This is The Ghost of the Lone Male Excavator! I just wanted to drop in and announce that I have nothing paleontological to report. Also, I await the next blog post from Andrea ...rattle, rattle, rattle...
Aloha.

2009-07-28T16:56:00.001-07:00

With Ryan gone, life is much daintier here at Rancho La Brea.

ping ping ping!

However, this does not mean that we are not still capable of great feats of strength:

once, this was a chisel. now, it is rubble. such is life.

as is evidenced by the still-growing pile of broken tools left in our wake (volunteer Meena broke this one...)

Thus, over the last week our girlie muscles have brought Deposit 7B down almost a meter below its original grade. 7B is small, and not densely fossiliferous, but nevertheless productive enough to stay interesting:

The femur is the latest of several sabertoothed cat bones we've excavated from this area (including a skull!), and we're wondering if they're all from the same individual animal. We won't know for sure until they're cleaned and officially identified by the folks in the lab.

Less immediately exciting, but still important: there's a huge chunk of rock hard oxidized asphalt right in the middle of the deposit. There are bones around this asphalt, but not in it. We think this might be a vent -- the fissure in the ground that the asphalt originally oozed up from! We've seen this in Pit 91 before, but haven't been able to observe it as well as now. We only worked in Pit 91 for 12 weeks out of the year, and would only excavate a fraction of the exposed grids each season. This means that though interesting geological features were documented, it would sometimes take years to see if they continued another foot below the surface -- just because it took us that long to excavate the entire floor. Working year round with smaller deposits is allowing us to focus on unexpected geologic/taphonomic environments like this one.

I mentioned the lab earlier, and soon we'll have a proper Update From Indoors but until then:

here's a soundtrack-less time lapse of the preparation of Zed's right femur. Still a work in progress, but you get the general idea. Email subscribers: visit excavatrix.blogspot.com to see the video. Or scroll down:

to see Zed's femur in it's shiny, well polished glory.

That's it for now, more later!

may the force be with ryan

2009-07-21T16:45:00.000-07:00

Sad but true: our Lone Male Excavator has left us for more exotic locales (grad school in plant and soil sciences on OAHU) and we miss him already. Ryan has been a careful and conscientious excavator, a funny dude, a good friend, and last but not least, an incredibly snazzy dresser (plaid + camo = AWESOME).

Yes, we will miss his hard work, his dedication to replacing shoring boards in the heat of summer, and his enviable ability to reach things on tall shelves, but we will also miss his encyclopedic knowledge of all things Star Wars, his willingness to talk in funny voices for our amusement, and perhaps most of all...

his unparalleled ability to re-purpose old broken office furniture during his lunch break. The above photo may appear to be an ordinary office chair, but look closer! It is actually an office chair attached to another chair because it broke off its original base. The wooden legs of the base chair have been careful sawed at an angle for maximum comfort.

And what became of the base of the chair, you ask? BEHOLD:

This is quite possibly my favorite piece of furniture ever. It's an end table! On WHEELS! This handcrafted beauty is made of another chair (with the back sawed off) screwed onto the base of the broken office chair, with a piece of laminate for a top. And it's the perfect height for chips and salsa!

Finally, Ryan's coup de grace:

A genuinely well-made desk for volunteer Christina, made out of the side of box 10B (I think it's 10B).

In conclusion: Ryan is awesome! We totally miss him! He is funny and us taught about plants and how to sharpen tools and such! However, on the bright side: we now have a couch to sleep on when we go to Oahu...

Godspeed, Ryan, and may the force be with you.

Final Note From the Lone Male Excavator

2009-07-14T09:16:00.000-07:00

Shore, -ing. (Verb):

the process of replacing old side-wall boards in large dug-out spaces (e.g., Pit 91).

This post will serve as both an introduction to some of the "other work" that excavators (and excavatrices) perform at Rancho La Brea and a documentation of the particular method of shoring board replacement that the Lone Male Excavator has developed.

So as the thick boards holding up the side walls of Pit 91 grow old, they often bow out, rot out, or both. Up above the pit, 14ft x 11 3/4" x 2 3/4" boards are stored ready to be cut to an average of about 75" long for use as a shoring board.

After a board is slated for replacement, of course it must be extracted. This is commonly far more difficult than it sounds. If the board is rotted to extremes on the ends locked in by the I-beams, then it is not too tough for a hatchet to cut through one end and pry the board out with a crowbar. If the board is not rotted away much at the ends, however, (as the boards pictured here) it can be quite difficult.

Initially, a cut with a circular saw is made through the board(s) being replaced. This is very dangerous and every safety precaution must be taken at this point (e.g., clean goggles, steady hands, hard hat). It is also messy and anything, including one self, which should not get covered in sawdust should be protected. If two parallel cuts, about 2" apart are made, extraction will be easier. Our cordless circular saw, however, does not cut deep enough to go through to the back of the boards.
So I have added to this method inspired by the wisdom of William A. Akersten's thought on sabertooth cat incisor (front teeth) functional morphology.

The points on large, cone-shaped incisors of Smilodon fatalis are separated to the extent that when they pinch together top to bottom and pierce into the skin of prey, they are thought to create a perforated line which allows for easy tearing off of chunks of flesh. When we are unable to pry/break out a board along the saw cuts, holes can be drilled along the cuts to create such perforated lines which can then be hacked trough easily or broken out through prying.Once a board is out, the wall of earth, often asphalt saturated, must be shaved a little with hand tools or, in dire need, a pneumatic chipper. Occasionally fossils are found in the side walls, so these must be watched for and documented when discovered.

Depending on the thickness of the new board and the bowing out of the old board shaving the walls may take up to a couple hours. Once this is done a measurement for the new board's length is taken, giving about an inch and a half behind the lip of each I-beam. (Often, when you think you've shaved enough and try to get the new board in, you find that a few spots need more shaving. The first of these two pictured here took me 3 attempts. I also found that I had cut it too long and had to take an inch off one end.)

After you've seen that the board will fit the space you've shaved out of the earth-wall, you must get it equally situated behind the lip of each I-beam... not so hard when you've got two-three boards out and you are doing the bottom board, but if you are trying to slide a single board over in a single space (like w/ the second board pictured) it can sometimes involve a long trial messing with crowbars. I have no solution, except putting in the lag screws early and trying to use them to slide the board. This does not often work.

If gaps are left, they are reduced by placing thin pieces of wood at the bottom of boards.

The boards are locked in between (and behind the lip of) I-beams which run about 40 ft under ground. As much of the board as possible is slid behind the inside of the I-beam before 5/16" holes are drilled beside the lip of the I-beam for 9/16" x 3 3/4" lag screws. The lag screws go through, what I'm gonna call, giant square washers which tighten the board flush to the I-beam. A thin, small piece of plywood is often needed between the shoring board and the giant square washer.

There you have it; Shoring 101. The final exam is getting a board replaced and not injuring yourself in the process.

So the Lone Male Excavator is off to grad school. This is my last day as an excavator at the Page Museum at Rancho La Brea, but I will still be around in spirit. (In fact don't be too surprised to see posts in the future by The Ghost of the Lone Male Excavator.)

a small but big discovery

2009-07-08T13:50:00.000-07:00

Hello! We found a very neat thing a few weeks ago:

It's a bird! It's a plane! It's-- wait, nope, it's a bird. The many small bones in the upper left-hand corner (with the big arrow pointing at them labeled "bird") are all from a small passerine, (or "perching bird"). These bones likely represent an associated individual; they were found in a slightly separate layer of asphaltic sand than the rest of the deposit, and some bones even appear to be somewhat articulated. In other words: this is the almost complete skeleton of a small bird; this is extremely rare; I have named him Kevin.

Though most birds are passerines, they are nevertheless rare at Rancho La Brea; our collections are dominated by bigger birds of prey like teratorns and condors. It's hard to say what species Kevin is, exactly -- especially without cleaning and preparing the bones first -- but Lab Supervisor Shelley says he's about the size of a scrubjay.

The bones in the numbered in this photo are as follows:

carpometacarpus
scapula
2 limb bones -- not sure which exactly
sternum
tibiotarsus? I think?
tarsometatarsus
femur?

The photo above was taken after removing a number of other bones separately, such as ...

the furculum...

another scapula...

...and a humerus (as well as an articulated synsacrum and femur, several vertebrae, and several phalanges that I don't currently have photos for). After removing these uppermost bones and discovering there were even more underneath we decided to remove the rest of the skeleton in one block...

which was accomplished by gently prying the layer of asphaltic sand it was rested in with well-placed screwdrivers and chisels.

Though this skeleton is exciting in and of itself, its context may actually be more important. As regular blog readers may remember, up until now Deposit 1 has been more dirt than fossils. There's a dense cluster of bones in the southeast corner that has yielded at least 1000 specimens (and at least that many more to come), but about 3/4ths of the box has been largely sterile. Not anymore. As we dig deeper into the so-called "sterile" areas, we've found a new layer of fossils:

This is a different style of deposition than in the "main" bone cluster we've previously worked on:

These fossils are spaced further apart, and spread out more evenly -- not all jumbled together like pick-up-sticks.
These bones are broken, weathered, and worn. The bones in the other cluster are largely complete
Many of the longer bones and bone fragments point in the same direction (scroll back up to the top of the page to get a closer look) -- perhaps implying stream movement? We don't know! But it's interesting...

Kevin was found in the northwest corner of this grid (near where the meter sticks cross) in a slightly separate layer of asphaltic sand -- perhaps implying that he flew in and got stuck after the rest of these unlucky beasts? Again -- we don't know! But also interesting! We will keep you posted as things and finds progress.

update update update wow.

2009-06-09T17:37:00.000-07:00

OH, we have been bad bloggers. Apologies for the complete and total lack of communication. BUT, in our defense, we've been really busy. Look:

This is Deposit 7B, and it is open for excavation. Now that 10A and 10B are done, lead excavatrix Kristen and curatorial assistant Aisling decided that the 7's would be next to go (while continuing work on the never-ending saga that is Deposit 1). According to APRMI's field notes and photos, the 7's are pretty fossiliferous -- more so than 10A and 10B, anyway -- and so far, the sediment hasn't been terribly hard -- good for excavators' hands, good for the fossils' relative safety.

Serendipitously enough: Shelley et al in the lab just opened another plaster jacket in the lab labeled "mammoth" only to find that it's actually half of a Giant Ground Sloth pelvis from near Deposit 7. Other finds from 7B:

From top to bottom: the ischium of a bison pelvis, an herbivore (possibly bison) rib, a cervical vertebra from a sabertoothed cat, a bit of plant, and a dire wolf humerus. We've also recovered another sabertoothed cat vertebra, another herbivore (possibly bison) rib, and a small piece of maxilla that may belong to a small dog or a mustelid of some sort -- we won't know until it's clean.

So, why has this taken up so much time? Well, I'll tell you:

Opening a new box/deposit isn't as simple as lifting up a tarp and digging in. First, we have to determine the box's original cardinal orientation -- that is, we have to figure out what side of the box originally faced north. More often than not, our imaginary north arrow isn't actually perpendicular to the northernmost side of the box; it's at an angle that can only be determined by carefully referencing original field notes from the salvage. It's only after we figure that out that we can set our grid lines, and begin digging. The diagram above (mid-pass from me to Laura) is a sketch of the overall layout of Deposit 7B, with every grid labeled, and the angle of that imaginary north arrow recorded for future reference. Did all that makes sense? If not -- comment, and I'll explain better next post.

So what else have we been doing?

The Page Museum hosted an Art + Science event in conjunction with LACMA's art walk. I put this 4 minute time lapse film-lette together for it -- PLEASE watch it; I think it turned out quite nicely! Time lapse experiments are largely responsible for stealing the time I would ordinarily spend updating the blog -- sorry! -- but I hope you will agree that the results have been worthwhile.

LACMA's art walk invaded our side of the park in a pleasantly chaotic sort of way:

These partially constructed hexagons of what would have been a geodesic dome spotted the hill surrounding the museum.

And these white and black tarps surrounded our sloth and bear sculptures! By the end of the day, they were re-purposed somewhat...

...as awesome space age forts for young paleontologists. More pictures, as always, if you click on the picture above and explore our flickr photo feed.

Speaking of social networking...

follow Laura on Twitter!

...especially when I'm MIA, or if more than 140 characters is just too much for you.

Finally, Michelle has recently discovered her true calling: she is a poet, and she didn't know it. Her specialty: the ancient Japanese form of poetry known as the haiku:

Working in Box 1
Ouch! I hit my hand again!
Chiseling is hard.

Dermal ossicles
There are many in this grid.
Natural defense

Glossotherium
Haikus can be so random.
Cheese quesadilla

Like I said, we've been very busy! Next update will be prompter, I promise!

update: the demise of deposit 10a, the flattening of deposit 1

2009-04-28T17:25:00.000-07:00

After about 8 months of digging, Deposit 1 is finally starting to look markedly different than it did when we first unveiled it -- well, to us, at least. Yes, it's still a dusty hunk of rock, but now it's a dusty hunk of rock that's around half a meter shorter than when we first got it.

As I've hopefully mentioned before, we work in 1m x 1m grids, and dig down 25 cm at a time. You've seen this before:

...the large, convoluted bone mass that was keeping us from "closing" grids B-1 and B-2 and moving on to other portions of the box. In both grids, we're working on level 3, which is the section of dirt 50-75 cm below the original ground level of the deposit. Does that make sense? Those large saber-toothed cat scapulae and innominates were sticking out above floor (the bottom of each 25 cm deep level) and needed to be removed before moving on.

Now the grids look like this:

Yes, there are still bones, but if you look carefully, you'll note a wonderful lack of scapulae...

...because Tara got the last one out! Everything left in place is too far below floor to excavate at this time. The grids surrounding the bone mass are still at level 2, so we have to get those down to level 3 before we can open up grids b-1 and b-2 at level 4. Did that all make sense? Excavational peccadilloes are difficult to describe via the interwebs. To sum up: if we keep excavating just the main bone deposit, we'll wind up with a giant hole in the ground (in the box) which will be too deep to keep digging at. So: sterile grids for us, for a while.

In non deposit 1 news: as Ryan and I have both mentioned, 10A is no more! We time lapsed it's final moments:

I have to say, I like the soundtrack to this one better than last week's, but I don't think anything will match excavation to the tune of "I Am the Walrus." Ah well.

Next week: we just laid grid lines out for 5 new deposits -- 7A-E! We're very excited to start work in new, softer dirt. Pictures soon to follow. OH! And click through to flickr to check out the giant freaky black (and brown) widows Laura and Michelle found under 10A.

more fun with time lapse

2009-04-23T16:53:00.000-07:00

We've been having a lot of fun with the built-in intervalometer on our new camera:

expect more videos like this in weeks to come! To our email subscribers -- the blank space you see above (and in my last post) is actually a youtube video embedded in the blogpost, which unfortunately doesn't seem to translate to email. Go to excavatrix.blogspot.com to view.

Note from the Lone Male Excavator:

2009-04-16T00:23:00.000-07:00

Y'all need to chime in and tell Andrea what a good job she is doing on this here blog a'ight!

We've got a lot done since my last post. Finished another box, matter-O'-fact (10A)! We've busted out them there scapulae from box 1 and got loads more dirt out to, eh.

Keep yer eyes open for a new "what is it" post coming soon!

-Ryan

8ish hours in 80ish seconds

2009-04-14T19:11:00.000-07:00

weekly update: all in a day's work.

2009-04-07T16:58:00.000-07:00

Yes indeedy, as Ryan pointed out last week, we have finished excavating our very first deposit from Project 23:

10B is no more! And its big sister 10A is soon to follow:

We're down to Project 21-and-a-half. The small patch of fossils from this deposit seems to have petered out. We can't be sure, but we're thinking the remaining few feet of dirt are largely -- if not entirely sterile. The boundaries between grids are left in place until they're completely exposed, and then mapped and photographed. This way, we can reconstruct the deposit's geology long after the deposit has been excavated.

And 5B looks much the same is it did last time I posted, only sans a level of plywood around the sides.

We're waiting to speak to one of the geologists who originally supervised the salvage before we begin digging.

Meanwhile, in Deposit 1....

We're still plugging away at the main bone jumble in Box 1. We've measured out at least another 100 fossils from this area. Right now, however, we're at a bit of a standstill, stuck between a rock and a hard place so to speak. Or rather, a scapula (shoulder blade) and an innominate (one half of a pelvis):

Pleistocene pick-up sticks once again! From left to right: we can't get the first innominate out without removing the scapula immediately above it, but we can't get that scapula out because of the saber cat vertebra immediately above it. THAT's stuck under the middle scapula, which is in turn pinned in place by next-to-last scapula, which is, of course, covered by both a cat humerus (lion or saber cat, not sure though) and yet another scapula.

This is all very detailed, very slow work. However, on the other side of Box 1, we get the other end of the paleo-work perspective:

This is Grid D-3/Level 2 at 9am. Mouse over to see it at 5. Or, just scroll down:

D-3 is largely sterile, except for the occasional articulated millipede or bit of plant matter. This means we can power through it as quickly as our muscles allow. Spencer and I worked on D-3 all day, and chiseled out about 5 full buckets of matrix! Hard, hard work, as evidenced below:

6 blisters on my right hand! Badges of honor, all.

Note from the Lone Male Excavator:

2009-03-24T08:31:00.000-07:00

What is a fossil? One of our readers, "Duys" in Belgium recently reminded me of how one can determine a fossil and I thought it a good time to bring it up. I'll meet that idea in a round about way here:

The other day, I held the back door for a family visiting the museum. One of them was in a wheel-chair and since the back (staff) door is nearest the parking lot, could enter there. Anyway, I was heading into the lab and so held that door open too so that they could get a peek inside at Shelley and the volunteers eating lunch and glimpse behind the scenes fossil workstations. The older gentleman pushing the wheelchair asked me if I was a fossil... "I'm getting there," I replied. (Yes, the LME turns 30 in less than a month.) This question the gentleman asked was not one we get often, but we are very often asked if the bones and other previously living materials we dig out are, in fact, "fossils."

Strictly speaking, it depends on your definition of the word fossil. When I took Invertebrate Paleontology, my professor, in the first week, was discussing some common mistakes & misconceptions in word definitions. One he mentioned was archaeology vs. paleontology, between which this blogs readers surely already distinguish the differences and similarities (yes?). Another he discussed was the difference between "fossil remains" and "recent remains," as well as how to tell if what you have is a fossil. Being a geologist, he discussed the difference in whether or not the remains had undergone mineralization. He noted that a fossil will not smell if you hold fire to it. Furthermore, if you stick your tongue to a "recent" bone it will stick a bit, but it won't with a "fossil" bone.

Geologists and dinosaur paleontologists often use this sort of "mineralisation" definition, but how do La Brea bones hold up to it? Since they do still contain collagen, Rancho La Brea bones would, hypothetically, still produce a burning organic smell if we held them to fire. And, yes, ones tongue would likely stick to them if tried, but that may be more due to the asphalt than the collagen.

So I've decided to test these hypotheses with a personal experiment. (Of course, I am not serious.) We don't need to burn or lick these bones to determine that they have collagen, as studies have already used collagen samples from many of the bones in attempts to extract proteins and DNA.

So, are they not fossils?
A 30,000 year old bone is a fossil, no matter how you slice it. Ancient Rancho La Brea bones, plant, shells, and insect parts all fall under the more encompassing definition of fossil provided to us by thefreedictionary.com:
"A remnant or trace of an organism of a past geologic age, such as a skeleton or leaf imprint, embedded and preserved in the earth's crust."

The Rancholabrean North American Land Mammal Age (named for our site) spans from
300,000 to 11,000 years BP, so being of a past geologic age, our remains in this time frame are fossils.

Here is a question for you all:
Are the bones, plants, shells, insect parts, etc., that we find and can date to less than 11,000 YBP fossils? Pit 10 contained a vent of remains, for example, dated at around 9,000 years. So these are not technically from "a past geologic age." Are these bones not fossils?

Since Andrea alluded to it in a previous post, I have to mention that a month ago I sprained my left wrist when I rode the top of a ladder to the ground...backwards and downwards, and slam. I have missed my left hand terribly and promise to never take it for granted again if it works with me on the physical therapy and retains full functioning.
Lawyers need not contact me, as the staff here and NHM human resources department have been caring and accommodating.

Oh, and FYI:
We've completed excavation of Box/deposit 10B; our first box finished. It went pretty fast because it was a disturbed (mostly fallen apart) deposit and we did not measure out any bones or use a grid system on it. We will not, be changing the project name to Project 22, but the thought crossed our minds.

help for the budding scientist

2009-03-11T09:08:00.000-07:00

Earlier this week I received the following email from a future paleontologist, Adrienne:

Hey, Andie, I have to do a science fair experiment... the kind where you have to answer a question like, "What different fruits and veggies have more vitamin C?" (That's an example, I did it in 5th grade (2nd place!))
Anyway, I have been searching the interweb and have been so far coming up blank. I was wondering if you guys had any ideas, anything that you remember possibly doing?

We never had science fairs at my school, so I have no suggestions for young Adrienne. But you, dear readers -- any ideas? If so, please comment away

weekly update/in the news: we're on basic cable!

2009-03-07T16:37:00.000-08:00

Lab assistant Trevor Valle made a totally awesome -- personable, even -- appearance on G4's "Attack of the Show" this week. Clip is embedded below!

Trevor had a great time, Kevin was a great interviewer, and we're hoping this'll turn into a recurring thing. Their studios are across the street, after all...

Meanwhile, back at the project...

We've taken a break from the large deposit -- Box 1 -- to focus on the little crate that could -- Box 10B. It's about 5' x 5' x 4' deep, and filled with wonderfully soft and squishy asphaltic sand and dirt -- SO much easier to excavate than Box 1. Not nearly as dense a deposit as Box 1, but we have found a wide range of rodent, rabbit and bird bones (including a beak), some dermal ossicles, and the jaw of a dwarf pronghorn. We're making quick work of this deposit; it's been open for about a month, and we're already more than half way done with it. Two things to note in this picture:
1) Check out the awesome lean-to that volunteer Richard Simun rigged up out of spare parts strewn about the excavation compound. We are well-shaded and sunburn-free!
2) The box was originally 2' taller than it is in the photograph; we've been removing slats from the tree box as we dig down. We'll be doing this for all of the deposits. It makes it easier to dig, and easier for the public to get a look at what we're digging.

Things you can't see in the picture above -- Ryan sprained his left wrist! But fortunately, he is going to be...

...a-ok. He's out of town now, but will have a "Note" on that sometime next week.

And though the sediment is a lot softer than that in Box 1 (I'm sitting next to it right now, with Spencer Bronte digging -- he just found a big bird bone!), it's not without its hazards:

I broke two screwdrivers this week while chiseling. Good time to test Craftsman's warranty, eh?

Note from the Lone Male Excavator:

2009-02-21T09:47:00.000-08:00

Inspired by our friend Jack Tseng's "What is this?" post, I've decided to place here a mystery bone and you all have to guess what it is. The winner will receive a short on-site tour of the Project 23 excavation site, or, if you are a Page Museum volunteer and have no prior knowledge of what it is, you will win a hearty handshake from the LME (Lone Male Excavator).

I want a specific answer, should be two parts: what bone is it? & what species (or I'll take family) is it?
Ideally, you should also say whether it is a right or a left and what developmental stage it is in (roughly how old was the animal).

weekly update: back to basics

2009-02-20T10:00:00.000-08:00

It has been one heck of a week here at Rancho La Brea; we were on almost every local news channel, the LA Times, the NY Times, the Brisbane Times, and even a couple papers from Norway ("We can not so many of these, such as deer to tigers sword" indeed!). In light of this newfound limelight (and in light of the exponential increase of blog subscribers!) I want to take a minute to get back to basics.

So for those just joining us: I'm Andie, and I work here, along with lead excavator Kristen Brown, fellow full-time excavator and lone male Ryan Long, and part-time excavators Michelle Tabencki and Laura Tewksbury. Project 23's intial beginnings are described in this blog post and many others found on this site. To date, we've excavated at least 700 fossils (and calculated a minimum number of individual animals of at least 2 dozen). Current tally includes at least:
-3 saber-tooth cats
-1 lynx
-1 North American lion
-6 dire wolves
-2 coyotes
-1 Harlan's Ground Sloth
-1 baby bison
-1 baby horse
-2 dwarf pronghorns
-LOTS of turtle
-at least 5 birds (including a teratorn!)
-LOTS of millipedes
-LOTS of oak leaves
and much much more

And our excavation site currently looks like this:

If anyone reading this works in the Variety building, we really want to take pictures from your rooftop...

Deposit 1 (on the right) is the first one APRMI found during the salvage, the biggest box overall, and the first one we started digging in. Also, it looks like a pirate ship, which pleases us immensely.

Deposit 10A (more lifeboat sized...) is also being actively worked on.

looks like Laura found a fossilized meter stick!

It hasn't yielded nearly as many fossils as Deposit 1, but did give us an interesting piece of turtle which might be new to Rancho La Brea, so that's pretty nifty.

Box 10B -- 10A's smaller, slouchier half -- is also being worked on, but can't be seen from the fence. Part of it collapsed while APRMI was boxing it up, however, so we're not taking as much locational data as we usually do.

And finally, Box 5B. We just opened this one a couple weeks ago, mostly to get an idea of what our next area of focus will be when we finish the 10s. We won't actively begin excavation until they're done. However, we've already found some neat stuff in it...

seriously: it is NOT A FOSSIL

...like this NOT FOSSIL wasp nest. It was on the side of the box under the tarp (again, NOT A FOSSIL). A neat instance of modern life co-existing (well, until the nest was abandoned..) with the extinct.

We continue to excavate 7 days a week (except for bank holidays and whatnot) and will happily talk to you if you stop by, provided we are not lunching, operating heavy machinery, or performing particularly delicate fossil extractions, and you do not try to throw things or yell rude questions (i.e. "Did you find my lost contact yet? Hyuk hyuk hyuk.") at us. We love our jobs, and love sharing our discoveries with you, and THANK YOU for your continued interest and support of natural sciences in general, and Project 23 in particular!

Additionally, there have been a number of questions posted as blog comments over the past week, which we'll answer ASAP. But as for now, we have some serious digging to do.

In the news (again!)

2009-02-17T17:22:00.000-08:00

Hey Angelenos -- Project 23 will be featured on the front page of the LA Times tomorrow! And be sure to check out their online photo gallery as well. And...

Hey early risers -- Project 23 will be on Good Morning, America tomorrow morning! We'll be popping up in all sorts of news outlets this week, so keep an eye out for more.

In the news

2009-02-08T13:42:00.000-08:00

Part-time excavatrix Laura Tewksbury has been busy! She sends us this link:

Whale Fossil for Concordia Elementary School

and writes:

"This was the first fossil preparation project I ever worked on, under paleontologist Greg Seymour. During high school, my mom would drive me over to volunteer at least once a week, and I got to both chip away at his (horrible, fine-grained, concrete-like) matrix and help teach the kids about paleontology. It's pretty much one of the main reasons I'm here [i.e. at Rancho La Brea]. I originally got involved through Dave Gerhard when he first moved to Concordia, since that was my old elementary school, my little sisters were still there, and my mom was PTA President.

How time flies. Like a whale on a hoist. "

Very cool, Laura!

update: PROGRESS

2009-02-06T12:13:00.000-08:00

Remember this?

Flip it upside down, replace employee Michelle with volunteer Christina, add in a heat gun, and you get THIS:

That, paleo-friends, is the skull of a North American Lion -- Panthera atrox. We finally finished removing all the bones around it, and thus successfully excavated the skull!

But first, here are some interesting inferences about North American Lions, provided by our fair leader, collections manager Christopher A Shaw:

- North American Lions showed up in their eponymous continent (North America) around 400k years ago

- They were probably not social animals -- in other words, there were no prides of these particular lions. We think this for two reasons:

We don't find nearly as many of them as we do dire wolves and sabertooth cats, and not with nearly the same range of ontogenetic age. For example, we've found approximately 6 North American Lions in Pit 91, compared to around 50 Saber-toothed Cats.
In a pride of African lions, the ratio of males to females is 1:6 or 1:7. Here at Rancho La Brea the ratio is about 1:1. Thus: no African Lion-esque prides. North American Lions likely had a more solitary lifestyle, more akin to that of a mountain lion.

- These lions likely did not have manes. Cave drawings in North America exclusively feature mane-less lions -- either that, or only females, which doesn't seem very likely.

Back to our skull: after months of carefully using dental picks to clear out the surrounding matrix, we eventually had to resort to brute force to get the lion skull out.

That's me on the left, Michelle on the right. I'm rocking the skull back and forth on its side to loosen it from the surrounding matrix; Michelle is holding on to a bone underneath the skull to keep it from coming out along with the lion. Aisling wisely thought to film the entire process:

Background soundtrack provided by: Marketplace with Kai Ryssdal on NPR; Laura Tewksbury singing; various lab volunteers cheering; and me saying "there's a frickin humerus attached to it!" A great orator, I am not...

Though quality on this video isn't the best, it is good enough to show just how tough it is to get something out of an asphaltic deposit. Even after putting all of my weight behind the skull, at first it barely moves. However, after some artful wiggling (and a decent amount of luck) it's out!

And there was much rejoicing! Yes, I could have continued removing matrix with the heatgun and a dental pick until the skull basically fell out. However, the more you use a sharp pointy object near a priceless artifact, the more likely it is that you scratch aforementioned priceless artifact (or one of the other 20 priceless artifacts under the skull that you can't even see and will therefore probably put a hole into). Thus, every once in a great while, it's better to use your bare hands and just push.

The skull itself is an absolutely beautiful specimen; it's the most complete P. atrox skull we've gotten out of the current excavations (i.e. Pit 91 and Project 23).

Look at all those bones I could have damaged had I continued using a dental pick! The crescent shaped bone in the lion's mouth is a horse hoof; there's a complete saber cat rib in the back; and yes, on the right -- there's a fricken humerus attached to it. Sabertoothed cat humerus, to be exact.

And now that the skull's out, we can get on with our excavation.

These are just a few of the bones that are now accessible thanks to the skull's removal. Click the picture above to be taken to our flickr site, where you can mouse-over individual bones and find out what they are.

As for our skull...

Laura promptly carried it off to the lab, and rumor has it that Herb will begin cleaning it in a few weeks. We think we'll name it Fluffy.

update-ish

2009-01-23T15:37:00.000-08:00

Too busy for a proper post, but if you click the photo above, you'll be taken to our flickr site, where I just uploaded about a dozen pictures from the filming of Dirty Jobs. More pictures next week, because friends, paleontology waits for no woman. We've had an extremely productive week, and just two short hours ago, we FINALLY got the North American Lion skull out of deposit 1. And let me tell you, it is a beaut. So once we're done basking in the glory of a job well done, we'll get back to blogging. Cheers!

DIRTY JOBS!

2009-01-21T12:47:00.000-08:00

l to r: Kristen Brown, Andrea Thomer, Michelle Tabencki (the happiest girl in the world), Mike Rowe (working the purple bandana like no other), and Laura Tewksbury

We excavators and excavatrices made our television debut last night on the Discovery Channel's totally awesome show, Dirty Jobs! Mike Rowe came by a few months ago to help us with Pit 91 maintenance. Tar pits were glopped, shoring boards replaced, fossils excavated, cell phones inexplicably thrown: in short, a good time was had by all. I have to say, Mike, Dave Barsky, and the rest of the Dirty Jobs crew were the nicest, funniest, and generally raddest film crew we've ever hosted at the pits, so many thanks to them for being great (and for not editing us to look like madwomen) (or rather, editing us so that you can't tell we're really madwomen).

Now. We have a TON of pictures from the filming of the episode, which will be posted to our flickr channel by week's end. AND we have a good amount of incrimintating footage of Michelle, excavatrix and sponge bather extraordinaire, which will hopefully be posted to youtube soonish (provided she lets me...). And AND for those of you that missed it, the episode will be playing again this Friday at 8pm on the Discovery Channel. Set your collective Tivos. And check back on Friday for more pictures and stories and tomfoolery.

go team awesome! l to r: Chris Shaw, Kristen Brown, Trevor Valle, Laura Tewksbury, Aisling Farrell, Michelle Tabencki, Ryan Long, Andie Thomer

Yay!

update

2009-01-13T16:12:00.000-08:00

happy non-denominational seasons greetings and new year

It is 85 degrees Fahrenheit in Los Angeles right now. In January. In what is supposed to be the dead of winter. We are mildly confused, but not complaining; digging in asphalt is so much easier in the warm sun! The matrix in two particular grids -- A-1 and A-2 -- has been soft enough to dig through using our fingers. Findings of note:

This jaw is from a small wildcat, most likely a Lynx, per collections manager Christopher Shaw. We don't have that many bones from smaller cats in our collection at the Page Museum for two reasons: 1) these smaller cats were likely solitary, so when they got stuck in an asphalt seep, they got stuck alone -- not with 15 of their closest friends, as with Dire Wolves and Saber-toothed Cats. 2) smaller cats have small bones, and early fossil collectors (during the early 1900s) would have likely passed them over for larger, more obviously interesting fossils like, again, those of the Saber-toothed Cat. This is what's called a collection bias: the arbitrary favoring of one kind of fossil or specimen over another. One of the main goals of the excavation in Pit 91 and with Project 23 is to correct this bias. Thus, we collect and keep everything -- even the stuff that might not seem obviously important at the time. For instance:

In grid A-2/Level 3 I found two bird tibiotarsi (i.e. drumsticks) immediately on top of one another. They're definitely from the same species (but I don't know which one), one tibiotarsus was a left and the other was a right, and they are about the same size. This may be a case of association (two fossils from the same individual animal), or it may be just a really weird coincidence. But it kind of doesn't matter: it's an unusual enough case to warrant thorough documentation. Pictures, notes, and measurements have been taken, and preserved for posterity. I am but a lowly excavatrix -- not a proper paleontologist -- and I haven't the years of schooling necessary to interpret this assemblage. But good data collection will hopefully benefit actual paleontologists of the future, as they dive through field notes and make the interpretations that we excavators couldn't. Ryan, our sole man, noted the following:

The orange bits are a complete oak leaf found from a largely sterile portion of Deposit 1. We've found a large number of plant parts, and a good number of oak leaves in this deposit. We don't know what plant is worth collecting and what isn't, so we try to collect as much as possible. Again, this is something for future scientists to interpret. And it's our job to make sure everything's collected in as complete a manner as possible. Finally, an eagle-eyed volunteer (hi Spencer) spotted the following:

a pile of orange dirt. While this wouldn't be surprising in any other fossil deposit, anything with any hint of color at the La Brea Tar Pits is worth noting. So a sample was collected, notes were taken, and hopefully this will give us some insight into the depositional environment around this particular deposit.

meanwhile, back in the lab (part II)

2008-12-30T16:14:00.000-08:00

When Shelley & Co. were about halfway done preparing Zed the Mammoth's thoracic vertebrae, they decided to open another plaster jacket: jacket #4, Zed's mandible! Their reasons were thus:

1) mammoth jaw means mammoth teeth. And mammoth teeth are excellent at revealing age. We already knew that Zed was fairly old when he died -- he's huge, for one thing, and there's evidence of arthritis on a number of his ribs, for another -- but we didn't know how old. Elephant tooth replacement occurs in very specific patterns, at very specific ages. They go through a total of 6 sets of molars in their lifetime, each molar slowly wearing down and getting pushed out by the one behind it. By comparing Zed's tooth wear to that of an African elephant, we can make a fairly accurate estimation of his age at death.
2) we have two extremely delicate mammoth tusks awaiting preparation. Working on Zed's similar-but-sturdier molars first may allow us to prepare for the tusks' preparation.
3) a very nice field producer from a very entertaining television show asked Shelley very politely to pretty please let them film the opening of the mammoth jaw jacket -- Shelley acquiesced. More on this when the time is right... [editor's note: oops, looks like I'm wrong. It was the thoracic vertebrae jacket that was opened on camera -- not the mandible jacket. Guess the field producer wasn't quite nice enough...]

Long story short: jacket number 4, containing mammoth mandible, was opened. And it looked like this:

Yuck! We were saddened to discover that a) the jaw is upside-down (no visible teeth means we must wait to learn Zed's true age!) and b) a tractor shaved off the bottom-most edges of the jaw, leaving what we in the business euphemistically call "discovery marks."

As you can see, Zed's matrix (the dirt surrounding the fossil)is primarily dusty brown clay -- not the dark, sticky asphaltic sand we find in Pit 91. This is good and bad -- good: it's easy to dig through; bad: it's dusty and dry. Dry means there's less asphalt in Zed's skeleton over-all; his bones may be a bit more fragile than many others found at Rancho La Brea. Shelley therefore decided to repair the bottom of Zed's jaw, giving it a solid base to rest on and preventing further damage. After the bottom half was cleaned and ready to flip, the jaw was built up with gray putty:

And a wooden base was constructed around it:

That pink stuff is cellophane. That wooden box is about to be filled with expanding foam, which will create a perfectly customized cradle for the jaw to rest it. The cellophane -- in addition to being quite fetching -- will keep the foam from sticking to bone.

Trevor assisting on the left, Shelley pouring on the right. The foam is created by mixing two separate fluids together, and waiting:

Look! It's Herb, waiting patiently! Herb is awesome; he volunteers here, and at the LA Zoo, and with the Dinosaur Institute at the LA Natural History Museum. He's basically enmeshed with every natural history organization in the greater Los Angeles area. I think he's trying to take over.

Anyway: the foam! It rises, like bread, but far less tasty:

Trevor shaved the few errant remnants, and then:

Yay! It's done! What a beautiful mandible base! The jaw itself was then very carefully turned, and placed into the base. Trevor removed another layer of plaster, and soon enough, Zed's molars finally revealed themselves.

Zed's on his last set of molars -- a pair of M3's. Mammoth teeth are similar to elephants in that they're made up of a series of undulating plates. These teeth erupt one after another, almost continuously throughout their lifetimes, and plates are worn down from front to back. Based on the amount of wear on Zed's teeth, Shelley estimates Zed's age at 47 years (+/- 2). Zed wasn't ancient, but he definitely would have qualified for AARP membership.

If mammoths lived as long as African elephants live now -- up to 60 years -- then Zed could have had another decade in him, had an asphalt seep not caused his tragic end. However, Zed's jaw contains a rather unexpected hint at what kind of life Zed would have lived. Look at the front of the jaw, between his molars, where his tongue would have rested:

That weird, drippy growth is pathological -- that is, it's not normal. While mammoths typically do have a kind of "spout" in that area -- sometimes it angles down, sometimes it points straight out -- they don't have the weird, bumpy, lopsided growth that Zed shows here. But here's the thing -- yeah, we know that growth is pathological. But just because it's weird doesn't mean it's necessarily uncommon. We have far fewer mammoths in our collection than we spoiled Rancho La Breans are used to dealing with -- 30-32, compared to thousands of dire wolves. And we have even fewer pieces of mammoth jaw. There are approximately five mammoth mandibles in our collection in which that particular feature (the mandibular symphysis) is more or less intact -- and certainly none anywhere as complete as Zed's. So it's hard to say if this growth is unusual or not. Who knows -- many mammoth mouths could have been lopsided and bumpy like Zed's. We won't know until we find more mammoths. All the more reason to keep digging.

But here's the other thing: several of Zed's other bones have pathological elements to them -- arthritic joints, broken and re-healed ribs. It's looking more and more as if Zed lived a pretty rough life. In fact, the latest jacket Shelley and Trevor opened -- just last week! -- contains another hint at Zed's life. But more on that next week. Or rather, next year. Whatever -- Happy new year!

meanwhile, back in the lab (part I)...

2008-12-23T17:14:00.000-08:00

As temperatures turn colder, it's time for The Excavatrix to turn attention to warmer, more indoor activities -- such as the preparation of mammoth fossils in the lab (not that we excavators aren't still stuck outside... come rain, sleet, snow and hail, excavation marches on...). Lab Supervisor Shelley, her assistant Trevor, and our wonderfully dedicated volunteers have been hard at work on two of the plaster jackets from Zed, our semi-articulated Columbian mammoth.

The first jacket they cracked open: Jacket #91, labeled "mid-vert column." This jacket contains seven of Zed's thoracic vertebra -- a portion of his spine that connects with his ribs. In fact, you can see part of one of the ribs in the photo below, immediately above our scale/quarter.

The proximal ends (the portions closest to the spinal column) of two ribs were encased in this jacket along with Zed's vertebra. And niftily enough, we were able to reunite both ribs with their missing halves:

We're always thrilled when we can actually put these paleontological puzzles back together with a minimum of sturm und drang. There are millions of specimens in our collection, and that's not including the bones that have been cleaned but not yet catalogued. The longer we wait to reunite fossils with their broken bits, the more likely it is that the reunion will never happen. In this case, both ribs were deliberately broken in order to make the jacket smaller and more stable, and thus allowing it to protect the vertebrae all the better -- a fairly common practice in paleontological salvage and recovery. However, in many cases, fossils are broken either by the act of deposition itself -- bones collide with other bones and break into bits -- or by accident, during excavation. Asphalt is hard, and mistakes are unfortunately made! These 23 fossil blocks are particularly difficult digging; Deposit 1 in particular is practically cement. So the sooner we can put the bone back together, the better.

Anyway, back to Zed's spine. This particular assemblage is a great example of what we mean when we say "semi-articulated." The photo below is a close-up of one of Zed's thoracic vertebra, and the rib that was found immediately next to it. These two bones would have been articulated, or jointed in life. However, their positions shifted slightly after Zed's tragic end. The two semi-circles would have been joined together in life, but now they're a bit misaligned. Hence, semi-articulated.

Eventually these ribs were removed to allow Shelley et al to finish cleaning the vertebrae. And finished product looks like this:

Lovely! This jacket is now on display in the museum, by the fishbowl laboratory! Please, drop by, say hello, check it out. More on lab activities next week, holiday schedules permitting.

weekly update: don't trust anything with more than four feet.

2008-12-05T14:17:00.000-08:00

You guys, I had a near death experience yesterday. It looked like this:

This may appear to be an innocent pile of rubble, but LOOK CLOSER!

Those legs! Those eyes! Those weird little pincher things! It is a SPIDER, people, and I did not get into paleontology to get CRAWLED ON and BITTEN by sneaky arachnids -- and yet this little guy and his cricket friends decided to jump all over me JUST BECAUSE I chiseled through their home. Blech. This is why I, personally, prefer invertebrates that have been dead for 10-40,000 years. Like these:

Millipedes! Or centipedes! Or maybe decapedes! A-lot-of-pedes! Whatever -- something that USED to have a lot of feet, but doesn't anymore and therefore CANNOT CRAWL all over me when I'm digging. In the particular grid that I'm working in, (C-2/L2 for those keeping score), there's a thin layer of green clay in between two layers of asphaltic sand, which is filled with compressed plant parts -- complete leaves in some cases, as Ryan found a few weeks ago -- and tons of insect/arthropod/etc remains all around. It looks like this:

Well, it more or less looks like this. Pretend that our digital camera doesn't get all washed out when it tries to photograph anything remotely black.

Per our boss, Collections Manager Christopher A. Shaw, this seam of green clay may be a layer of oak leaf litter -- thus, Deposit 1 was once surrounded by a grove of oak trees.

Meanwhile, on Deposit 10A, excavation marches on! We had another near-death experience last week, when we found what looked suspiciously like naturally occurring asbestos. Fortunately, we were totally wrong -- it's nothing but Epsom salt, and we are panicky excavators. So, here's to not getting mesothelioma!

yay! not dying!

We're only about 20cm below the original surface of Deposit 10A. But so far we've found several pieces of tortoise shell -- almost unheard of at Rancho La Brea until now -- and a near complete pond turtle shell.

update, of the weekly variety

2008-11-21T09:48:00.000-08:00

it's Photo Collage Madness 2008! Click through to our flickr.com page for highlights and more photos.

Gallivanting in Mexico aside, paleontology marches on here at Rancho La Brea. The grid that had been giving us so much trouble two weeks ago has met its match, and its demise:

l to r: Saber-toothed cat humerus, giant ground sloth vertebra, dire wolf skull.

The dire wolf skull had been upside-down in the grid; once we got it out and flipped it over, we discovered that it was heavily grooved and pitted as a result of pit wear. Or, in other words: there's a hole in his head! Observe:

On the left: a dire wolf skull with a gaping hole in his forehead. On the right, our fair leader Kristen (who will hopefully be joining this blog in the near future), forehead still intact. Click through to our flickr site for more close ups (of the dire wolf skull, not Kristen)...

In other news:
-we've measured out approximately 34 bones since Oct 31st.
-we just opened a new deposit: number 10A. Photos forthcoming.
-we've made a great deal of progress in our mapping -- the entire surface of deposit 1 has been sketched and stitched together. Again, photos forthcoming.

Note from the Lone Male Excavator

2008-11-17T13:30:00.000-08:00

Hi all. I'm still here, treading in a sea of tar and estrogen.

In an attempt to be more like Andie, I've decided to put up another post and to start reading occasional comic graphic novels instead of just paleomammalogy and Harry Potter books, as has become the habit. I found this graphic novel of the first 10 comics of "Y, The Last Man" about this guy who ends up being the last man on Earth after all the rest die from something (don't know yet what, but I think it must be something to do with an attack on some phenotype from the Y chromosome, eh?).

Anyway, this guy is left alone in a world full of women, so I thought the series highly appropriate for me. We'll see.

Anyway, pulled this juvenile Smilodon vertebra out the other day (see pic). It is a very confused vertebra; it does not know whether it's an individual vertebra or part of the sacrum. This is a sort of developmental disorder likely caused by genetic problems and not uncommon in Smilodon. You can see (compared to the adult normal vertebra in the pic) that one side of the bone thinks it is a normal vertebra and the other thinks it is part of the sacrum. Furthermore, the neural spine is both off-center and angled wierd. I thought this one was pretty neato, but Michelle is the excavator, excuse me, excavatrix, who is really into pathologies.

This is one of the sweet perks to having such a large collection/set of deposits like Rancho La Brea: not only do we get a clear picture of the complete skeletal morphology of members of our fauna, but we get a very good knowledge of the pathologies which affected them.

Also see below the complete leaf I uncovered yesterday!

the-past-two-weeksly update: no news is good news

2008-11-14T14:44:00.000-08:00

No weekly update last week because we were in beautiful El Golfo de Santa Clara in Sonora, Mexico collecting fossils! We camped in the desert for five days; collected numerous ice age (but older than RLB) fossils; watched many beautiful sunsets; and returned home to the rather sobering realization that excavating at the La Brea Tar Pits for one day leaves one even grimier than camping in the desert (without showering!) for five. Gross, right? Anyway...

This is El Golfo:

View Larger Map

And this is us:

From left to right, standing: Laura Tewksbury, Trevor Valle, Robert Predmore, Melody Weaver, Chris Shaw, Michael Wilson, Andie Thomer. Kneeling: Fred Croxen, Aisling Farrell, Ryan Long

El Golfo de Santa Clara is a magical land, where cars glide along the ocean:

And boats wind up on the street:

And fossils are NOT in tar pits! Oh no! They are lying on the ground, for everyone to see! See all the little rocks in the picture below?

A good number of those are actually very small fossils. Geologist Fred Croxen (in the center, with the jaunty hat) is bagging up rocks and dirt from the surface, which will then be sifted through in mesh screens:

and eventually sorted through under a microscope for the same kinds of microfossils that we find here at Rancho La Brea. The fossils from El Golfo are considerably older than those here -- 1 to 1.5 million years old, compared to our measly 10 to 40 thousand -- but nevertheless contain many similar species as our tar pits.

More soon!

view from the top

2008-11-03T09:39:00.000-08:00

Over the weekend, I put together a faux-panorama of the top of Deposit 1. Standing in the northwestern corner of the deposit, I did my very best David Hockney impression and photographed everything I could see from there, and then overlaid the images in Photoshop. Though its not nearly as helpful as a wide-angle photograph would have been, I think this still gives a good idea of what the overall deposit looks like. The fossiliferous grids are (so far) all in the eastern portion of the box; most other grids are sterile (no fossils). If you click on the image above, you'll be taken to our page on flickr.com (where we store all the photos featured on this blog, as well as many others), where you can mouse-over different parts of the photo to read descriptive notes.

weekly update: happy halloween!

2008-10-31T16:22:00.000-07:00

We here at Rancho La Brea pride ourselves on our holiday spirit.

Michelle. Devilish excavatrix extraordinaire.

Unfortunately, Michelle took her Halloween persona a little too seriously today, and placed a hex on grid B-1.

The face (and index fingers) of evil.

Because ever since SHE worked in B-1 yesterday, we've come to a near standstill in fossil extraction. All of the bones are intertwined with one another, and completely STUCK in place. The big dire wolf skull is stuck on top of the lion skull, and the sloth vertebra is stuck next to the dire wolf skull, and the saber-toothed cat humerus is pinning the vertebra in place, etc etc etc. It is a veritable portrait of frustration. Observe:

VERITABLE, I say!

Curse you, devilish Michelle! And curse you B-1!

This week's tally:
-33 bones extracted, including that juvenile saber-toothed cat skull fragment:

Shelley's Halloween costume: hand model!

At first, we thought we'd broken the saber during excavation, but after closer inspection, it looks like the hole in the center of the tooth is the natural result of pit wear -- the erosion of bones caused by other bones as they all jostle around in the tar pit.

- We also got the second-to-last dire wolf skull out:

Photo by Michelle.

Happy Halloween!

weekly update: dogs and cats, living together, mass hysteria!

2008-10-28T17:17:00.000-07:00

Yeah, it's messy, but does your office have lightsabers and power tools on the same shelf?

We're gonna try to make this weekly update thing happen, like, every week. On Fridays. But not this past Friday, because Blogger ate my last update before it posted properly (curse you, Google...). Thus, we're a little behind, so this is more of a The-Past-Two-or-Three-Weeks update.

So, The Past-Two-or-Three-Weeksly tally:
- 120 bones measured out between Oct 10 - 24

notable finds:
- the coracoid of a Teratornis merriami (Merriam's teratorn). Teratorn's were huge birds of prey; their name means "monster bird" in Greek; they had a 13' wingspan; and they looked kind of like gigantic condor-vulture hybrids.
- the radius of a Capromeryx (dwarf pronghorn)
- again, a whole grip of ribs from a whole bunch of animals, all laying on top of each other. Excavating them has been like playing pick-up sticks in a graveyard, but we finally got at least a dozen out of the way, including three complete vertebral (as opposed to sternal) ribs.
- several Giant Ground Sloth caudal (tail) vertebrae and haemal arches (mini-psuedo-vertebrae that articulate with the underside of caudal verterbae)
- the semi-complete underside of a turtle shell. This was found in a section of the deposit that we previously thought was sterile, which is very, very good news -- more bones means less boring fossil-less dirt to dig through.
- Dogs and cats are peacefully co-habitating in grid B-1; we've found 3 dire wolf skulls so far (2 are pictured below), various bones from at least 2 coyotes, various bones from at least 2 saber-toothed cats, and as Ryan previously posted, the skull of a North American lion has been uncovered, but not yet excavated.

Grid B-1, Level 2, as of October 24, 2008

One of the dire wolf skulls (from a particularly old individual -- his teeth are worn down almost to the root) is directly on top of the lion skull.

highlight of the north american lion skull. mouse-over for the highlight of the dire wolf (if the image doesn't immediately shift, wait a few moments for it to load, and try again).

- as I previously posted, the saber of a saber-toothed kitten has been exposed.

look!

As you can see, saber-toothed cats were born with little sabers, which makes one particularly pity the saber-toothed mothers...

notable events:
- After months of excavation, Kristen got the giant ground sloth scapulas out!!

and grid B-2 has gone from this:

to this:

That's a giant ground sloth ulna in the center. Eventually, I hope to plot the location of all sloth bones in Deposit 1 to get a better idea of how, exactly, the animal's skeleton fell apart.

Once again: progress!

today...

2008-10-18T20:10:00.001-07:00

we found two saber-toothed KITTEN sabers! completely amazing. pictures forthcoming. wait, with bated breath, you shall....

Note from the Lone Male Excavator:

2008-10-16T23:12:00.000-07:00

I have often been asked what it is like to work as the lone man among four women. I usually reply in one of two ways. On a good day I say, "It is awesome to work with four talented, intelligent, beautiful, tough women." On a day when I am forced to watch The View and/or Oprah during break times I say, "There are good days and bad days." In essence each of my responses is true, but overall, I work with four people that know, as I do, that we have one of the coolest jobs on Earth. Though our tight-knit group is a socially intense and complex small band of hominins, it is this author's opinion that intragroup cooperation is facilitated quite readily by the composition of individuals and the male to female ratio.

Now, I'm sure you've heard enough on that matter for this post, and even if you have not, too bad, because I have something far more interesting to discuss:
We have partially uncovered the skull of a North American "Lion" (Panthera atrox). I'm sure that pictures will be posted of this find as we make more progress in removing the bones still above it and, finaly the skull itself. From what we have seen so far it is at least fairly well preserved. As was noted in an earlier post, we have also found a P. atrox pelvis. The skull was found in the same grid only a few inches below. We are curious as to how many of the many ribs and vertebrae and other bones found in this grid might also be attributable to P. atrox. Many of the bones in this grid have been of Smilodon [including a complete saber (upper canine)] and it is not always easy to determine an identification of the more general bones until they have been cleaned in the lab.

Well (2!), until next time...

measure for measure

2008-10-15T16:35:00.000-07:00

Earlier this week, we measured out the left half of an American Lion pelvis (or, more anatomically correctly, an innominate). Whilst typing this into yesterday's entry, I realized I've never actually explained what "measuring" a fossil entails, let alone why we do it.

"Measuring out" a fossil means recording the location of two to three of the bone's anatomical points (usually three) within the context of a 1m x 1m x 25cm grid. For instance, take our most recent innominate:

The three dots and abbreviations above represent the three different anatomical points: IC stands for Illiac Crest; PT means Pubic Tubercle, and DP means Dorsal Posterior (which isn't actually a point -- it's a general orientation. This portion of the bone is broken off, so there isn't an actual feature to measure. Instead, we measure an arbitrary point, and name it after the point's location in the body: Dorsal, or toward the spine, and Posterior, or toward the rear end).

Each of these three points gets three pieces of data of their very own: measurements of the fossil's location below the original surface of the deposit (abbreviated as "BD" for "Below Datum"), north of the southern most line of the grid (N), and west of the easternmost line of the grid (W). These measurements are written into our field notes, and carbon copied (literally, with little blue pieces of carbon paper) onto 3" x 5" cards. Confused yet? Fear not, it sounds much more complicated than it actually is. But here's an enhanced version of the final product:

Remember Algebra class waaaay back in 9th grade? Wait, let me rephrase that -- remember any of the math from Algebra class waaaay back in 9th grade? Yeah, me neither. However, had you paid closer attention to the graphing portion of your text (and less attention to Spitball Trajectory 101), you would recognize those three columns of numbers as coordinates within a 3-dimensional graph. For example, for the IC, x = 43, y = 42, z = 32.5, etc. By recording all of these coordinates, we're able to later reconstruct the fossil's position within the deposit. And in doing that, we can learn all sorts of nifty things about how skeletons fall apart within a tar pit, or which animal got trapped first, or how asphaltic sand shifts underground over time, and so on and so forth.

A better photo narrative of a fossil's journey from grubby, dirt-covered groundling to a finished, fully prepared specimen is forthcoming, but until then, I hope this has been helpful. Or, at the very least, has inspired you all to pay closer attention in Algebra II.

this week in urban paleontology

2008-10-14T17:52:00.000-07:00

Busy, busy excavators we have been!

The photo above shows the 50+ fossils we've measured out over the last two weeks. Extremely note-worthy finds include:
- a metacarpal (hand bone) of a Capromeryx (an extinct and fairly rare species of dwarf pronghorn)
- numerous saber-toothed cat and dire wolf ribs
- at least 6 sub-adult thoracic vertebrae (vertebrae from the rib cage) of a saber-toothed cat. We think they're all from the same individual animal! They were all found in the same 50cm X 50cm x 25cm area of the fossil deposit, and all appear to be about the same age. This is the sort of semi-articulation or association that we've been so excited about finding, because we very rarely (if ever) find it in Pit 91.
- part of a dire wolf skull
- at least four coyote jaw pieces
- a sloth sternal rib (a rib from the front of the ribcage, rather than the back. If you can't find one in your own torso, don't worry -- humans do not have sternal ribs. If you do find one in your own ribcage, please let us know! We'd be extremely interested in studying you...)
- the astragalus (an ankle bone, AKA the talus in humans), scapula, and pelvis (pictured below) of an American Lion

the measured pelvis, in it's natural environment: a metal bucket and a plastic bag. more on this tomorrow

What does this mean? Well, we've found not just one, but TWO of Rancho La Brea's rarer species (the American Lion and the Dwarf Pronghorn) in our first month of digging, not to mention another unique instance of fossil association! This first deposit is already adding to our knowledge base, and these discoveries bode well for the rest our excavation.

And remember this?

(l to r: sloth left scapula, sloth right scapula, ryan)

it now looks like this:

(l to r: dustpan, sloth left scapula, yet another tibia, sloth rib, sloth right scapula, michelle)

Progress!

update!

2008-09-28T09:13:00.000-07:00

Long time, no update, but with good reason: we finally officially "opened" our first fossiliferous grid in our first fossil box from Project 23, and we've been too busy digging to blog. Hopefully, some pictures will make up for the thousand or so words we have not written.

Below, a view of B-1 circa a few weeks ago:

roll-over for highlight

The three highlighted bones above are all tibias, and are all from the right leg. However, they're from three separate animals:

From left to right, you're looking at lower right hind leg bones of a coyote, a dire wolf, and a young saber-toothed cat.

We finally got the saber-toothed cat pelvis off the top of the grid:

Note the pelvis-shaped impression in the ground to the left.

Volunteer-of-the-Century Harry made us a brand new tool box:

which now holds our brand new phone, our brand new field notebooks, our brand new meter sticks, our really-old-but-still-totally-useful comparative collection of dire wolf and saber-toothed cat carpals and tarsals (wrist and ankle bones), and, apparently, my three-hour-old cup of coffee.

And speaking of volunteers, we've started bringing them up to help us dig! Tara-the-ever-persistent, of course, was our first:

And finally, we put together a small exhibit for the museum explaining how Project 23 came to be:

The two ribs on the left of the case are from our semi-articulated mammoth; the rib on top is normal, but the rib on the bottom has a large bump in the middle from a break that healed during the mammoth's lifetime. Zed (as the mammoth has been dubbed by lab supervisor Shelley Cox) has several broken-and-re-healed ribs on his right side; he must have sustained a massive injury which he subsequently recovered rather nicely from. And the fossil block on the right is the same block of skulls that came from the "blob" we wrote about last month. The brown vertebra in the middle is from Zed; the white vertebra above it is from Jenny:

Shelley borrowed an Asian elephant skeleton from the Natural History Museum and has been using it to help identify Zed's (much larger, but still comparable) elements. In the photo above, Shelley is comparing Zed's ribs to Jenny's (Zed's are La Brea brown; Jenny's are white).

More soon!

databasing

2008-09-16T17:44:00.001-07:00

One of the most frequently asked questions we get here at the La Brea Tar Pits is one so deceptively simple sounding that it regularly stumps us out of sheer, monosyllabic force. It's not that we don't have an answer -- it's just that the answer is exponentially longer and more complicated than the question.

That question, of course, is "Why?" Why, with a collection of more than 3.5 million fossils, do we keep digging? Don't we have enough fossils? Do we really expect to find anything new?

Some of the answers to these questions, in reverse order, are:

1) We find something new every week, if not every day. Not a new species necessarily, but things like a new and uniquely laid out deposit of fossils (such as our two associated sloth scapulae), or new information on the geology of the deposit. Mini-discoveries like these help color our continually evolving picture of the Pleistocene in Los Angeles. Now, new species are difficult to come by, but with this new project, we have sheer volume on our side. With the amount of fossiliferous dirt we have to dig through, we'd be surprised if we didn't discover a new type of animal.

2) You can never have enough fossils.

3) Now, the big question -- the big "WHY?" There are far more answers to this question than we could possibly cover in one meager blog entry, and many of which we hope to touch on in coming months. As for now, you'll have to settle for this lovely and informative graphic put together by one of our most dedicated volunteers, Tara Thara:

Click on the diagram above to be taken to Many Eyes website, where you can play with the image a bit more extensively. Currently, we're looking at the age of individual vertebrae organized by taxon; if you click through to Many Eyes, you can change that to compare, say, age by depth, or taxon by grid, etc etc.

Man, computers are great. One of the many many reasons we have to keep digging is because with statistical comparisons like the bubble diagram above (created from our Pit 91 Vertebrae Database), the more data, the better. In this chart, we're using the ontogenetic age (the developmental age of the bone) of different vertebrae to generate an estimate of how many very juvenile, juvenile, sub-adult, and fully adult animals we have in Pit 91. And from that information, we can make inferences about the animals' behavior in life. For instance, the large number of sub-adult saber-toothed cats found at Rancho La Brea has led some (such as my boss, Chris Shaw) to believe that Smilodon was a social animal -- the young cats would have gone after a trapped herbivore in the tar pits with their fully grown relatives, and all gotten stuck at the same time.

Now, the caveat to this -- the idea that more data creates more reliable statistics -- is that the dataset must be somewhat complete. Pit 91 hasn't been totally excavated yet -- we've got another 3-8 feet of asphalt to dig through, which equals tens of thousands of more fossils to find -- and we won't be able to make any final conclusions until we're done. On top of this, the database itself isn't complete; again, we have thousands of fossils that have been excavated and identified, but still need their data entered into the computer. However, with Project 23, we're hoping to enter the information into a computerized database as we dig. And since we'll be digging year-round with a much larger staff (as opposed to 12 weeks in the summer with a staff of two) we'll be able keep on top of data entry, and we'll be able to finish excavating each deposit in a much timelier fashion (i.e. under than 30 years).

So that, readers, is one of many reasons why we must keep digging. Population studies demand more data! Databases demand more data entry! And basic human curiosity demands that we slowly, steadily, someday reach the bottom of our inverted Everest.

attack of the 3' x 4' blob

2008-08-08T12:14:00.000-07:00

In addition to our 23 fossils boxes (and 327 buckets, 20 plaster jackets, assorted ziploc baggies, etc etc) we've acquired a number of what we've been affectionately referring to as fossil blobs.

Several of the deposits were too large to place into buckets, but too small to box up. Consequently, they were carefully chipped out the ground, lifted onto wooden palates, and brought over to the Pit 91 compound. The asphaltic matrix (the dirt and "tar" between the bones) has melted and softened in the sun since the blocks' removal, giving some of them a distinctly melty appearance. Hence: fossil blobs! The 3' x 4' x 2' blob pictured above is the largest of them all, and we originally thought that the dire wolf skull (lower right hand corner) was the most interesting thing about it. However, as we reached the end of the blob, we uncovered the following melange:

left/front

I know it doesn't look like much, but fossil Number 1 is actually one side of a bison jaw, Number 2 is the back half of a sabertoothed cat skull, and Number 3 is the horn core of a bison skull!

Paleontology -- especially paleontology at Rancho La Brea -- is occasionally more about nimble fingers and well-trained eyes than it is about the science of evolutionary biology. With these three specimens, that has definitely been the case. There was so much matrix surrounding the fossils, and so few immediately identifiable features that it took us about four days to fully realize what, exactly, we were digging up. The bison jaw was the first thing we were able to identify --

bottom

the teeth are kind of a dead give away (the jaw is upside-down, mind you)-- and after that the sabertoothed cat skull quickly came into view:

back

In the above photo, we're looking at the back of the roof of the cat's mouth. This skull in particular was encased in extremely hard, dry, brittle clay. It took an entire day to gently chisel away the matrix without damaging the paper-thin bone underneath.

top

And finally, the horn core. Now. I desperately wish I could take credit for identifying this rare and unusual specimen, but, in actuality, I stared at the dang thing for two days straight without realizing what I was looking at.

I lose five paleontology points.

OMG DOS

2008-08-07T15:40:00.001-07:00

OMG DOS FTW, originally uploaded by the excavatrix.

No, dear reader, this picture is not from 1987. It's from a week and a half ago.

Fossils come in many forms...

i still think we should try stilts

2008-07-18T21:27:00.000-07:00

So we have all these boxes of fossils, right? And we have all these excavatrices (and Ryan) to dig the fossils out. No problem, yeah?

look! look how happy we are! how happy, and... how short.

Problem, yeah: At least four of the tree boxes (forgive me, fossil boxes) are well over 10 feet tall, and therefore well out of the reach of even our tallest paleontologists. Consequently, the past week has been spent figuring out how to essentially turn our Pit 91 excavation methods upside down. We gathered, we discussed, we brainstormed, and we eventually decided on...

A jungle gym! Yes! And the teeter totter will be installed next week.

Clearly, reader, I am joshing you. However, suggested (and summarily rejected) ideas for excavational elevation included stilts, a trampoline, moon shoes, and hovercraft technology. We settled on scaffolding (kindly donated by a certain excavatrix's father) and old reliable:

An extendable ladder. Genius, I know.

But wait, there's more! Look:

we built a RAILING! Gravity, your charms will ensnare us no longer! We are safe as houses. And check out the view -- we've got box seats for LACMA's Saturday evening latin jazz.

Life is good. Even without stilts.

The story thus far

2008-07-09T15:22:00.000-07:00

Between February and July of 2006, 16 ginormous fossil deposits were found underneath what used to be Ogden Dr. (and what is now LACMA’s fancy new underground parking garage). With construction deadlines looming and fossils constantly appearing underfoot, Robin Turner over at APRMI came up with a brilliant plan: rather than halting construction for an indefinite period of time to excavate each and every fossil, she boxed the deposits up as if they were colossal oak trees, lifted them out of the earth with an equally colossal crane, and set them aside for later study. These 16 deposits took up 23 tree boxes, and thus….

"PROJECT 23" WAS BORN!
(Well, “Project 23 plus 2 fossil trees, 327 buckets, a whole bunch of film canisters and plastic baggies filled with other assorted fossils, and 20 plaster jackets containing the bones of one semi-articulated mammoth with complete tusks," but you get the idea, right?)

So what's in these boxes? We don't know! It's a mystery! We won't know until we open up them up! It's like a paleontological Christmas! If the deposits are anywhere as dense as Pit 91, we could have literally hundreds of thousands of fossils on our hands. And if we were to include all of the microfossils (bug parts and tiny shells) in that estimate: maybe even millions.

That having been said, we do know this:

This is the top of Deposit 1, and these are the bones of a sabertoothed cat. But furthermore, these are the semi-articulated bones of a sabertoothed cat: a hip bone and a lower hind leg, to be exact. Further furthermore, we know that these are the bones of a fairly young sabertoothed cat; since the epiphyseal line between the main part of the bone (the diaphysis) and the end of the bone (the epiphysis) is visible, we know that the animal was young enough that his bones hadn't finished fusing. We rarely, if ever, find this sort of articulation in Pit 91. The fact that we're finding this sort of thing right off the bat is fairly-to-extremely awesome.

Further further furthermore:

This is the scapula (shoulder blade) of a giant ground sloth (and Ryan's feet) (please note the tar-y socks). Giant ground sloths are AMAZING and made entirely of WIN, and their presence in this first deposit is an extremely good omen.

More soon...

it starts...

2008-06-28T11:47:00.000-07:00

The Excavatrix

Our Blog is moving!

We opened another box!

How to Screen Wash Project 23 Matrix

Cleaning and the Media

New Staff Lounge

Winter Update

Trevor's Lab Update and words on National Fossil Day

Updates!

an overdue farewell

The Great Volunteer Bucket Moving Day

Introducing Box 14

Farewell to Deposit 5b

camelops!

project 23 on 'best of la'

why working in a public park is fun.

Monarchs at Pit 91

we're back!

update: more sabertoothed cats and kittens

update: out of 7A, back in to deposit 1

what we did over our summer vacation:

Boo!

may the force be with ryan

Final Note From the Lone Male Excavator

a small but big discovery

update update update wow.

Twitter Updates

update: the demise of deposit 10a, the flattening of deposit 1

more fun with time lapse

Note from the Lone Male Excavator:

8ish hours in 80ish seconds

weekly update: all in a day's work.

Note from the Lone Male Excavator:

help for the budding scientist

weekly update/in the news: we're on basic cable!

Note from the Lone Male Excavator:

weekly update: back to basics

In the news (again!)

In the news

update: PROGRESS

update-ish

DIRTY JOBS!

update

meanwhile, back in the lab (part II)

meanwhile, back in the lab (part I)...

weekly update: don't trust anything with more than four feet.

update, of the weekly variety

Note from the Lone Male Excavator

the-past-two-weeksly update: no news is good news

view from the top

weekly update: happy halloween!

weekly update: dogs and cats, living together, mass hysteria!

today...

Note from the Lone Male Excavator:

measure for measure

this week in urban paleontology

update!

databasing

attack of the 3' x 4' blob

OMG DOS

i still think we should try stilts

The story thus far

it starts...