Maryland Geological Survey 251 



its large size; convex left valve and flat or concave right one; large, 

 triangular wing ; small well defined ear ; and strong, rounded rays on the 

 left valve, with smaller intermediate ones. 



Length parallel to hinge-line, of about an average specimen, 37 mm.; 

 length of hinge-line, about 40 mm. ; height, about 45 mm. and extreme 

 distance from beak to base, 54 mm. 



Occurrence. — Eomney Formation, Hamilton Member. East bank 

 Evitts Creek below Wolfe Mill; Town Creek Eoad at George Diefen- 

 baugh's ; on National Eoad ^ mile west of Tonoloway Eidge ; on Oldtown 

 Eoad, east of Maryland Ave., Cumberland; on Hancock-Harrisonville 

 Eoad about 2 miles north of Hancock; on National Eoad northeast of 

 Cumberland; along Flintstone Creek in Gilpin; west of iron bridge over 

 Town Creek, northeast of Oldtown; east side Warrior Mt. east of Eush; 

 on road about half way between Eomney and Hanging Eock, W. Va. ( ?) . 



Collections. — Maryland Geological Survey; New York Stqte Museum; 

 American Museum of Natural History. 



Pterinea sp. 

 Plate XXIX, Fig. 5 



Pterinea sp. undet. Kindle, 1912, Bull. U. S. Geol. Survey, No. 508, p. 91, pi. 

 viii, fig. 4. 



Description. — " The collection from southwestern Virginia includes two 

 left valves of an undetermined Peterinea. The best-preserved specimen, 

 which is figured, though nearly flat, shows evidence of having been mod- 

 erately convex in the crumpled fracture line resulting from pressure. 

 The shell is large and erect; height and length nearly equal; margin 

 regularly curved. Hinge-line straight, equal to or greater than the 

 greatest length of the shell. Beak anterior; ear small, limited by a dis- 

 tinct sulcus ; wing broad and rather sharply delimited from the rest of the 

 shell. Surface of the valve marked by strong elevated radii which are 

 separated by wide flat interspaces. These show a slight posterior curva- 

 ture in the upper portion of their course. The ear and wing are marked 

 by radii of much less strength than the body of the valve, but the entire 



