MARYLAND GEOLOGICAL SURVEY 705 



Occurrence. MONMOUTH FORMATION. Brightscat, Brooks estate near 

 Seat Pleasant, 1 mile west of Friendly, 2 miles southwest of Oxon Hill, 

 Prince George's County. 



Collections. Maryland Geological Survey, Philadelphia Academy of 

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



Outside Distribution. Magothy Formation. Cliffwood clay, New 

 Jersey. Matawan Formation. Merchantville clay marl, Woodbury clay, 

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

 Red Bank sand, New Jersey. Black Creek Formation. North and South 

 Carolina. Eutatu Formation (basal). Exogyra ponderosa zone, Chatta- 

 hoochee County, Georgia. (Tombigbee sand member.) Exogyra ponder- 

 osa zone, Mortoniceras subzone, Stewart County, Georgia. Ripley Forma- 

 tion. Exogyra ponderosa zone, Stewart County, Georgia. Exogyra 

 costata zone, Eufaula, Alabama; Union, Tippah and Alcorn counties, 

 Mississippi. Extreme top of zone, Pataula Creek, Georgia; Chattahoochee 

 Eiver, Alabama. 



LEPTOSOLEN ELONGATA Weller 



Leptosolen ? elongata Weller, 1907, Geol. Survey of New Jersey, vol. iv, p. 

 627, pi. Ixx, figs. 27, 28. 



Description. " The dimensions of the type specimen, a cast of the left 

 valve, are : Length 24 mm., height 8 mm., convexity 2.5 mm. Shell 

 elongate, dorsal and ventral margins sub parallel; anterior margin 

 rounded, its greatest extension above the mid-height; posterior margin 

 probably rounded or truncate, not completely preserved. Beaks small, 

 terminal, but little elevated above the hinge line. Valves closed in front, 

 apparently gaping behind ; the surface regularly convex from the dorsal to 

 the ventral margin, curving a little more abruptly above and inflected to 

 the hinge line in the anterior half of the shell; curving abruptly to the 

 anterior margin in front. In the cast a strong, deep, sharply denned 

 furrow extends downward from the beak towards the ventral margin, and 

 a little obliquely backward, curving a little posteriorly near its lower 

 extremity ; another much less conspicuous furrow originates beneath the 

 beak with the first one, and extends backward, parallel with the hinge line, 



