Beschreibung:
<p>A new genus and species of bivalve mollusk found in the upper part of the Ripley formation in a cut of State Highway 30, 3.4 miles northeast of New Albany, Union County, Mississippi, is described under the name Hilgardia compressa Stephenson in the family Mytilidae. This shell is unusual in that among hundreds of collections no representative of the genus has been found elsewhere in the Upper Cretaceous of the Atlantic and Gulf Coastal Plain.</p>