Maryland Geological Survey 323 



of Belemnitella, the Bohemia Creek fauna is notable for the relatively 

 large number of Ostreids, a feature which it shares in common with the 

 later Matawan and the Navesink of New Jersey. It differs from the 

 Navesink, however, in the absence of a large gastropod fauna. Appar- 

 ently the waters were even more shallow in the area inhabited by the 

 Belemnitella than in that characterized by the presence of Sphenodiscus 

 and by the relatively few Ostreids, particularly those of the more ponder- 

 ous type. The Sphenodiscus fauna is restricted in its known distribution 

 in Maryland to the Western Shore and, indeed, to Prince George's County. 

 The marls containing these forms have furnished the most prolific fauna 

 of any of the Upper Cretaceous deposits of Maryland. There is clearly 

 no basis either on faunal or stratigraphic grounds for recognizing south 

 of the Delaware the subdivisions of the New Jersey area, although the 

 Monmouth fauna is extensive and characteristic. 



Among the most characteristic Monmouth forms common to Maryland 

 and New Jersey are: Ncmodon eufaulensis, Ostrea monmouthensis, Exo- 

 gyra costata, Pecten simplicius, Liopistha protexta, Crassatellites vadosus, 

 Cardium kummeli, Corbula crassiplica, Anchura pennata, Turrit ella 

 paravertebroides, Gyrodes petrosus, Eutreplioceras dehayi, Sphenodiscus 

 lobatus, Belemnitella americana. 



The Eancocas fauna has not been discovered in Maryland, although it 

 is quite well represented in Delaware in the vicinity of Odessa, not far 

 from the Maryland Line. The diagnostic features of the fauna are essen- 

 tially those of the Vincentown of New Jersey — a prolific bryozoan fauna 

 with Terebratula harlani in abundance and a very meager molluscan rep- 

 resentation. The mollusca of the two areas are curiously dissimilar, none 

 of the few characteristic species of New Jersey — Cardium lenappi, Caryatis 

 veta, Polorthis tibialis — occurring in Delaware, while the abundant Dela- 

 ware Grypltaza to which the characteristic Vincentown bryozoa attach 

 themselves is apparently not present in New Jersey. It is probable that 

 the Delaware Vincentown represents a fossil oyster bank where the 

 ensemble of the life was, as it is to-day, very distinct from the fauna a 

 short distance removed from the bank. 



