MARYLAND GEOLOGICAL SURVEY 645 



The species is unusually abundant and well preserved at Brightseat, 

 Prince George's County. 



Occurrence. MAGOTHY FORMATION. ? Good Hope Hill, District of 

 Columbia. MATAWAN FORMATION. Post 157, Chesapeake and Delaware 

 Canal, Delaware; Ulmstead Point, Anne Arundel County, Maryland. 

 MONMOUTH FORMATION. ? Millersville, Anne Arundel County; Bohemia 

 Mills, right bank of Bohemia Creek near Scotchman's Creek, Cecil County ; 

 east of mouth of Turner's Creek, Kent County ; Brightseat, railroad cut 

 west of Seat Pleasant, Brooks estate near Seat Pleasant, 1 mile west of 

 Friendly, McNeys Corners, Fort Washington, Prince George's County, 

 Maryland. 



Collections. Maryland Geological Survey, Philadelphia Academy of 

 Natural Sciences, New Jersey Geological Survey, U. S. National Museum. 



Outside Distribution. Matawan Formation. Merchantville clay marl, 

 Wenonah sand, New Jersey. Monmouth Formation. Navesink marl, 

 Eed Bank sand and Tiiiton beds, New Jersey. Black Creek Formation. 

 North and South Carolina. Eutaw Formation (Tombigbee sand mem- 

 ber) . Exogyra ponderosa zone, Mortoniceras subzone, Georgia ; Prentiss 

 County, Mississippi. Transition beds, Eutaw to Selma. Exogyra pon- 

 derosa zone, Mortoniceras subzone, Dallas County, Alabama. Ripley For- 

 mation. Exogyra ponderosa zone, Barbour County, Alabama. Extreme 

 top of zone, Pataula Creek, Georgia. Selma Formation. Exogyra pon- 

 derosa zone, Lee County, Mississippi. Exogyra costata zone, Wilcox 

 County, Alabama; east-central Mississippi. 



Superfamily ASTARTACEA 

 Family CRASSATELLITIDAE 



Genus CRASSATELLINA Meek 

 [Hayden, 2d Kept. Geol. Survey, Territories, 1871, p. 300] 



Type. Crassatellina oblonga Meek. 



" Shell transversely trapezoidal, equivalve, inequilateral, with free 

 margins closed and smooth within; hinge with two cardinal teeth, and 

 one elongated anterior and one posterior lateral tooth in each valve; 



Etymology: Diminutive of Crassatella. 



