Tuesday, February 24, 2015

Four and Counting!

Things have gotten weird in the last couple of weeks. Jerry Dodson is starting to work on another big block, Block 1, where we have identified two skull parts exposed on the surface. They won't be full skulls, of course, since they are broken where the block broke. So here is Jerry's current project. We've run out of table space so it's on a wheeled hydraulic lift table.

I don't know if these holes in the bones are semi-circular canals for ear balance, but they certainly could be.

Here's the block after a large section came off. There are skull bones at the upper end and lower end of the removed block.

I continue to work on good 'ol block 2 which I've been slaving away for two+ years.  I started chasing a small bone cluster on the surface of the break plane between block 1 and block 2 - hah!

I know the bone to the right is part of a centrum. The one in the middle was interesting, and I thought the small bone to the upper right was part of a rib - wrong! There actually were  four bones on this cluster - 2 centrums and two others. The 'others' are the interesting ones. So here I have cut away around the outside of the ones somewhat, digging my normal trench to remove them. They actually went quite deep and when I tried to knock them off....
 This is what happened! The end of the entire block broke off, exposing a beautiful Nautiloid!  It's really quite big.

And it's a species we haven't seen before. The sutures look like a nautiloid, but the sides of the animal don't have the typical indented whorls. Instead, they resemble some of the more globular ammonites. It is a lower priority (and shells are difficult to prepare) but it's still going to be interesting. A new species, perhaps?

So here's the cluster of bones. I think one is a section of mandible while the other one is a thin part of a skull, maybe around the orbit. Full identification will have to wait until they are fully prepped. 

Last of all, when the block broke off it exposed yet another bone clustered with the ones I originally started with. However, preparing this bone revealed a wonderful surprise - it's ANOTHER BRAINCASE!!!! This makes 4 total now - so we have at least four animals!!!!

And to be even more interesting it's about 30% LARGER than the largest one we had (which was the previous largest one) - so we have a growth sequence of four individuals all different sizes! It will take another 3-4 weeks to get this one out as most of it is still in the main block buried deeply. However it's really worth pursuing. 
 Here it is back on the block, with the other full braincase for comparison.

Like I said, it's been a crazy couple of weeks. 
Sincerely, Greg Carr

Friday, February 13, 2015

Chasing out more Skull Fragments and an unexpected Bonus

Since the last post we have been actively taking off the large blocks three pieces of what look like more skull fragments. Since they are still embedded we don't know how large they are, but we have hopes.

Two of the fragments are located on block 1, which we haven't done much work on. Almost all the work over the last two years have been on block 2. I've had to reduce the hour I spend actively scribing due to tendonitus. So I started by pulling out block 1 and removing the plaster. It is as big as block 2 and shares a common cleavage plane so it should be just as productive. Lo and Behold after cleaning we find two skull fragments showing on the surface. Jerry has been given the opportunity to dig them out. Here is a closeup of one of them. There appears to be some large holes in the bones right in the center of this picture. These may be semi-circular canals, though they are much too large to fit in the brain case bone where you'd expect them. We have another scrap with holes like this showing. It will be great to compare the two.

Here's an overview of the block 1 with the part shown above directly in the middle and another skull fragment above it (shown to the left as the picture is turned).

Here is a closeup of possible skull fragments on block 2 / block 1 cleavage plane. Some of this may be centrums, but part is definitely more skull fragments.

Here is block 2 after the end was knocked off to access the skull fragments better. To the right you can see a wonderful invertebrate shell. The sutures look like a nautiloid, but the overall shape is that of a spherical ammonite. We'll just have to see what is is after removal.
 Here is a closeup of the shell. It is really big - over 3 inches across - and will be complete! The lip of the opening is visible, so we have the entire shell.
 Last of all, I have made an archival cradle for the large left side skull roof fragment. I followed the same steps as making the full skull cradle. First, prepare an oversized plywood bottom to be the base.
 Next, wrap the bone in aluminum foil to keep it clan, and apply a layer of clay about 1/8 inch thick tomimic the future foam padding.

Then make up plaster re-enforced with chopped glass, and embed the bone clay-side down into the plaster. You have to work fast as the plaster sets in about 6-10 minutes!
 Last, after the plaster sets remove the clay and aluminum foil and add the padding. Good for a hundred years!

Sunday, February 1, 2015

Another Month, More Skull Parts

We have been focusing on bones that appear to be skull parts since they tell us so much about new animals, and are generally very descriptive and unique. We know from having three brain cases that we have parts of three skulls in this first block we are excavating. We now have as well three specimens of the left side of the skull roof that include the pineal gland. I believe these are found in the parietal and frontal bones.

Here is the latest bone - the anterior part (front part) is toward the left with the midline running along the top of the piece. This piece has a very delicate part left on the rear-projecting spur on the lower left in this picture. I believe it is the supratemporal and the squamosal. These are missing from the other two pieces.

Here are a couple of closeups of the posterior projection of the spur. The fin is only about 1 mm thick and (of course) it was difficult to prepare. 

This one shows the interior of the braincase and the pineal gland as well. 

Here is the one before that. I can't seem to find it totally prepared in this same position, so here it is with the anterior end (front end) pointing up. The pineal is the notch on the right side, the brain case in the lower projection on the right. 
 And here is the third one. It is the most broken piece, but the pineal and some of the midline suture rugosity is evident upon inspection.

When we get these all together we will compare sizes. It is my impression that the largest piece is actually from the largest skull, but it awaits accurate dimensioning. Two of these fragments are already in Alaska so I can't do it right now. I have begun scanning parts with two new students at Century High School. After all the skull bones that are here in Oregon are scanned they will be sent to the U of Alaska, Fairbanks, to join the rest of the skull parts. 

Sincerely, Greg Carr