With clear weather this morning, we set off early with a reduced crew, as Brooke and the students headed off to do stratigraphic work. The rest of us went to the site to try and finally remove one of the two vertebrae in the pit. But how to go about removing a thin, delicate, fractured bone that’s wedged above and below by two other bones? In the image above, the vertebra is in the center, the possible tibia is the mass to the left, and the rib is in front just above the scale bar. Here’s the annotated image from my field notes (TS2-11-09 is the vertebra we’re trying to remove):
Here are the same bones, but with the camera held in front, parallel to bedding:
Notice how the vertebra is sitting directly on top of the rib, and also pokes up underneath the possible tibia on the left. This required a tricky and time-consuming removal, starting with tunneling around the vertebra from each side while being careful not to bump against any other bones. All this had to be done with very limited work space; fortunately Nancy and Linda didn’t mind getting cozy:
After the plaster set, instead of immediately flipping the bone we had to first pull it out sideways to avoid damaging the other bones, and then flip it. The jacket remained intact, and then the final test – how did the rib underneath do? Completely undamaged!
I spent 17 hours over two days working on just this vertebra, and that’s after several other folks had already worked on it. But the time was well spent; if we had gone more rapidly we would have ended up damaging one or more of the bones. Tomorrow we’re going after the rib.