Chesapecten jeffersonius

Did you know that each state in America has a designated state fossil? This large, extinct scallop is Virginia’s! It was the first North American fossil illustrated in scientific literature, published in 1687 by Martin Lister. Lister was an influential naturalist and is considered one of the first individuals to suggest a geological survey as a useful map of a given region. Although he never visited North America, his publication put an image of this fossil into the scientific literature while Jamestown was still the capital of Virginia. Lister’s two young daughters, Anna and Susanna, are credited in many of Lister’s works as his illustrators and engravers. One of the girls, who would have been 13 and 14 years old at the time, may have drawn the specimen their father analyzed.

The Chesapecten jeffersonius is characterized by 9-12 ribs and a rounded shell edge. The name was given in 1824 to honor famous Virginian and interested natural historian, Thomas Jefferson. Quite an honor to have a fossil named for you during your lifetime! In 1975, it was associated with the new genus Chesapectin, named for the Chesapeake Bay region in which these fossils are found. The scallop shells can be huge, up to about 7-11 inches across, and their presence is used to determine the Miocene-Pliocene boundary in Virginia, with Chesapecten jeffersonius belonging in the Early Pliocene, or 4.5-4.3 million years ago.

There are at least four complete valves and many fragments of the C. jeffersonius in the Jamestown collection. They were likely picked up by the colonists, just as we do today, for their personal collections. Their large size and stability would have lent to the shells being used in various ways – perhaps as a candle holder, a ladle, a drinking cup, or a bowl. Can you imagine other uses of C. jeffersonius?