MARYLAND GEOLOGICAL SURVEY 



EOCENE, PLATE I 



NOTE: The Nanjemoy formation is divided into the Wood- 

 stock member which consists of argillaceous greensatids, and into 

 the Potapaco member which is composed of argillaceous sands above 

 and clays below. The Aquia formation is divided into the Paspo- 

 tansa member which consists of ledges of greensand marls under- 

 lain by greensands, and the Piscataway member which is composed 

 of inter stratified layers of indurated greensand marls and incoherent 

 greensands. 



