Our Blog is moving!

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!

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

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

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): http://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

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.