THE LOWER CRETACEOUS DEPOSITS OF 



MARYLAND 



BY 



WM. BULLOCK CLARK, ARTHUR B. BIBBINS, 



AND 



EDWARD W. BERRY 



INTEODUCTION 



A knowledge of the Lower Cretaceous deposits of Maryland can only 

 be secured througli an understanding of the physiography and geology 

 of the broad province of which the State of Maryland forms a part. The 

 physical features which characterize this area may be traced for varying 

 distances into adjoining regions^, some being recognized as far as the 

 ISTew England coast on the north, and others as far as the Gulf Eegion 

 on the south. 



The Physiography 



The region here considered forms a portion of the Atlantic slope, 

 which stretches from the crest of the Alleghanies to the sea, and which 

 is divided into three more or less sharply defined regions known as the 

 Coastal Plain, the Piedmont Plateau, and the Appalachian Eegion. 

 These three districts follow the Atlantic border of the United States 

 in three belts of varying width from New England southward to the 

 Grulf. Maryland is, therefore, closely related in its physiographic fea- 

 tures to the States which lie to the north and south of it, while its 

 central location on the Atlantic border renders it perhaps the most char- 

 acteristic in this broad tract. In crossing the three districts from the 

 ocean border the country rises at first gradually, and then more rapidly, 

 until it culminates in the highlands of the western portion of the State. 



