Makyland (Jkological Survey 133 



comparison with Orhiculoidca mimda (Plall) and this opinion was com- 

 municated to Prof. Schuchert. He WTote, however, after examining 

 the specimen that it is a Pholidops and that the shell of " Orhiculoidea 

 minuia is more phosphatic and does not show the strong concentric 

 growth lines as in this specimen." The other specimens he said " arc 

 hardly good enough to make out and yet what one can see agi-ees with 

 PJiolidops hamiltoniae. The Pholidops have great distribution and it is 

 safe to say that you have the F. hamiltoniae." 



Length, 1 mm. -|- ; width, about 1 mm. 



Occurrence. — Romney Forjmation, Onondaga Member. William? 

 Road 3^ miles southeast of Cumberland and 25 yards west of Oriskany 

 contact. 



Collection. — Maryland Geological Survey. 



Pholidops of. areolata (Hall) 

 Plate IX, Figs. 0, 10 



cf. Pholidops areolata Hall, 1863, IGth Kept. N. Y. State Cab. Nat. Hist., p. 31. 

 cf. Pholidops areolata Hall, 18G7, Nat. Hist. N. Y., Pal., vol. iv, p. 31, pi. iii, 



figs. 4, 5. 

 Pholidops cf. areolata Kindle, 1912, Bull. U. S. Geol. Survey, No. 508, p. 70, 



pi. ii, figs. 7, 8. 



Description'. — " Shell broadly subovate or scarcely circular, wider on 

 the posterior third, broadly rounded behind and more narrowly rounded in 

 front. The cast of one valve (the dorsal valve?) shows a deep ovate or 

 subcordiform muscular scar, which is nearly surrounded by an elevated 

 areola, and partially divided by a median ridge from above. The opposite 

 (ventral?) valve has a larger muscular scar, which is auriculated above, 

 with the surrounding areola divided at the lower or anterior margin. 

 Surface somewhat abruptly flattened on the posterior side, and more gently 

 sloping on the front of the valve." Hall, 1867. 



" The shell is subovate, the width of the posterior portion being slightly 

 greater than that of the anterior. Surface marked by strongly lamellose 

 concentric striae. The mold of the interior of the ventral valve shows a 



