World Turtle Day

According to American Turtle Rescue, May 23 is World Turtle Day (hat tip to Clifford Blizard from the Atlanta Nature Examiner for pointing this out). This event reminded me of a short excavation that took place along the Potomac river back in October 2003, shortly after Hurricane Isabel hit Virginia.

Hurricanes cause a lot of erosion and often expose new fossils, so as soon as possible after the storm, I headed to Westmoreland County with the museum boat, accompanied by then-graduate student Susan Barbour Wood  (Susan has since graduated from Virginia Tech and is now a geology professor at Western Carolina University). About 70 feet of Calvert Formation is exposed along the cliffs in Westmoreland County.

On our second day, we found a few turtle bones exposed about 10 feet up the cliff:

Digging along a river presents its own unique set of challenges…

But over a period of 8 hours or so we were able to uncover a substantial number of turtle remains, all included in a single jacket:

We removed the jacket the same day, and the next month I was able to open the jacket and prepare it. It quickly became clear that we had more of the turtle than we had initially realized:

When it was all finished we had a substantial part of a sea turtle shell. In the photo below, the anterior (front) end is to the right. The left front of the shell is largely missing; that’s the part that had already eroded from the cliff. Not included in the photo are several marginal plates and five or six dorsal vertebrae that were also collected.

The shape of the shell plates, and in particular the complex ornamentation on their external surfaces, show that this specimen is referable to Syllomus aegyptiacus.  Syllomus is a small cheloniid turtle that is very abundant in the Calvert; large numbers of specimens have been collected from Westmoreland County over the years by VMNH and the Smithsonian, and we have more than 100 individual Syllomus bones from Carmel Church.

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