Its official state fossil is Chesapecten Jeffersonius
[DOC] [TLE] Maryland's Official State Fossil Shell - Maryland Geological Survey [PAR] As of October 1, 1994, the official fossil shell of Maryland is an extinct snail, ... to a 
fossil clam, now known as Chesapecten jeffersonius, which appeared in Lister's 
... to the fossil from Virginia (thus giving its name priority), the scientific name of... [DOC] [TLE] Chesapecten jeffersonius | Updates from the Paleontology Lab [PAR] Sep 28, 2009 ...