MARYLAND GEOLOGICAL SURVEY 203 



Length, 1 1 mm.; height, 8 mm. 



Occurrence. — Naxjkj[()Y Formation. Woodstock, Head of Nanjemoy 

 Creek, Charles Branch butwecii Kosaryville and Upper Marlboro, Popes 

 Creek, East and west of Port Tobacco, Upper Marlboro (deep cut near 

 Chesapeake Beach E. R. station), 2| miles above Popes Creek. 



Collections. — Maryland Geological Survey, Johns Hopkins University. 



• MOLLUSCOIDEA. 



Class BRACHIOPODA. 



Order TELEOTREMATA. 



Family TEREBRATELLIDAE. 



Genus PLATIDIA Costa. 



Platidia marylaxdica n. sp. 

 Plate LYIII, Figs. 1, la, lb, Ic. 



Description. — Shell small, subcircular, somewhat depressed, with well- 

 marked lines of growth; ventral valve with hinge-area prominent, high, 

 bisected by a large open foramen and with a well-defined, linear septum 

 in the interior; dorsal valve with large pedicle incision, and with a short, 

 high, slightly bifurcated medium septum in the interior; teeth and 

 sockets prominent; shell structure minutely punctate. 



This beautiful little brachiopod is not uncommon at Upper Marlboro 

 where it is found associated with bryozoans and foraminifera. There is 

 no other American fossil species of this genus. 



Length, 4 mm.; width. -1 mm. 



Occurrence. — Aqula Foematiox. L^pper Marlboro. 



Collection. — Maryland Geological Survey. 



