30 The Lower Cretaceous Deposits of Maryland 



in character. The Rancocas formation, which outcrops in Delaware 

 near the Maryland line, consists of greensand marls which are fre- 

 quently highly calcareous. 



The organic remains consist chiefly of fossil plants in the Earitan 

 and Magothy formations, and of fossil invertebrates in the Matawan, 

 Monmouth, and Eancocas formations. The flora consists largely of dico- 

 tyledonous types those forms found in the Raritan formation being dis- 

 tinctly Cenomanian in character while those of the Magothy are ap- 

 parently Turonian in age, which is apparently also the age of the 

 Matawan invertebrates. The Monmouth fauna, corresponding to the 

 Ripley fauna of the Gulf, is universally regarded as of Senonian age, 

 while the overlying Rancocas fauna has been referred to the Danian. 



The total average thickness of the Upper Cretaceous formations of 

 Maryland is about 400 feet. They show a dip of from 20 to 35 feet in 

 the mile to the southeast. 



TERTIARY 



Eocene 



The Eocene is represented by the Pamunkey Group, which consists of 

 the Aquia and Nanjeraoy formations. The deposits are of marine origin 

 and comprise part of a geologic province embracing Virginia, Maryland, 

 and Delaware. 



The two formations constitute a conformable series which overlies the 

 Upper Cretaceous deposits in Maryland unconformably while in Virginia 

 it has transgressed the latter and is found overlying the Lower Cre- 

 taceous strata unconformably. The deposits consist chiefly of green- 

 sands which are often calcareous in the Aquia formation and argillaceous 

 in the JSTanjemoy formation. 



The fossils consist mainly of animal remains and comprise an ex- 

 tensive fauna, embracing particularly the group of Mollusca and Anthozoa, 

 which shows a faunal relationship with the Wilcox and probably with 

 the lower Claiborne beds of the Gulf. 



The total thickness of the Eocene deposits in Maryland is about 235 



