There’s not a great deal to report today, as Tim and I spent most of our time removing overburden to widen the pit; I estimate that we moved a little over two tons of material today. We did uncover a few as-yet unidentified bones, and tried to find the distal end of the rib that we exposed on Tuesday (the long, curved bone above). We couldn’t find the end of the bone, however, because it’s hidden under a large rock (the round object in the center, below):
This actually illustrates an important point quite well about the relationship between the bonebed and the conglomerate. When we first began excavating at Carmel Church, we weren’t sure of the age of the conglomerate. It sits on top of Eocene Nanjemoy Formation, and the bonebed is in the Calvert Formation, so at first we only knew that the conglomerate was somewhere between 14 and 50 million years old. With further excavation, we began to notice relationships like the one shown above, in which large rocks from the conglomerate are sitting on top of fragile bones that have not been reworked. This shows that the conglomerate and the bonebed formed at the same time, and since we know the bonebed is about 14 million years (based on land mammals and diatoms), we know the age of the conglomerate as well.