MARYLAND GEOLOGICAL SURVEY 



115 



low cliff, is composed mostly of a dark, lead-colored clay, and is overlain 

 abruptly with Talbot sand and gravel, while unconformity on the ^Miocene 

 is beautifully shown at the base of the Bay shore section. A number of 

 fossils have been described from the Cornfield Harbor locality, among 

 which are Ostrea virginica Gmelin, Area ponderosa Say, Area transversa 

 Say, Venus mercenaria Linne, Mya arenaria Linne, Barnea eostata 

 (Linne), Crepidula plana Say, Polynices dnplicatus (Say), and Fulgur 



Fig. 4. — Diagram showing pre-Talbot valley. 



carica (Gmelin). In this exposure the lower 4 feet of clay carries the 

 marine forms and above this there are 2 feet of sandy clay literally packed 

 with Ostrea virginica. These same general relations hold for the similar 

 deposits south of Cedar Point. 



The stratigraphic relation of these lenses of clay which are surely 

 unconformable on the underlying formation and apparently so with the 

 overlying sand and loams of the Talbot formation is a problem which 

 engaged the attention of the autlior until it appeared that the apparent 

 unconformity with the Talbot, although in a sense real, does not. h<nv- 



