This morning it was cool and foggy, but around lunch time the sun finally came out, so we were able to get a lot of work done today. While waiting on the pit to dry out a bit we continued working on the area just to the east of our first jacket, which has to be removed to get at the remaining vertebrae from our whale. We’ve had to slow down, though, because there are all kinds of additional bones there, including at least three whale vertebrae (they’re hard to see because of all the mud):
We’re now close to being able to jacket these remains, but the big task for the day was to flip Monday’s jacket, which contains vertebrae and a flipper. I’ve been worrying over this jacket all week. To flip the jacket effectively we need to be able to undercut most of the way around it. With this jacket we simply couldn’t get into the back to undercut it. There were bones everywhere, and some places where we couldn’t get a pick to go into the ground. I was especially concerned because the ulna was sitting very close to this area, and there was a big chance of it falling out of the jacket or breaking.
By 3:30 it was finally dry enough to make an attempt at flipping; in the photo at the top of the page I’m removing the pedestal supporting the jacket. My concerns weren’t realized, as the jacket flipped perfectly. Once it was removed it became clear why we couldn’t get a pick in the back; there was a huge rock in the way:
The bottom of the jacket makes an interesting study on the topography of the formation boundaries. When we turn a jacket over, the bottom is essentially a flat horizontal surface, but since the boundaries between the formations are not flat they are seen as discontinuous in the jacket:
There is even a little bit of Choptank Formation (the unit that overlies the Calvert). The Choptank is filling the burrow from some invertebrate that dug a hole in the Choptank seafloor, through the Calvert, the bonebed, and the conglomerate, and into the underlying Nanjemoy Formation.
Here’s the finished jacket:
And finally, another interesting feature that was visible after the jacket was removed. The big lumpy mass in the photo below is a rock, while the arrows are pointing to two bones directly under the rock. This is another example of evidence that the bonebed and the conglomerate were formed at the same time, contrary to the assumption we made in the early 1990’s that the conglomerate was older than the bonebed.