THE CAMBRIAN AND ORDOVICIAN 

 DEPOSITS OF MARYLAND 



BY 

 R. S. BASSLER 



INTRODUCTION 



The Cambrian and Ordovician deposits of Maryland can only be 

 interpreted through an understanding of the geology of the extensive 

 province extending from eastern Canada to Alabama, of which the State 

 of Maryland forms a part. The Cambrian and Ordovician formations of 

 Maryland extend far beyond the confines of the state and in adjacent areas 

 to the north or south frequently afford more satisfactory evidence of their 

 character and fossil content than they do in Maryland. 



THE PHYSIOGEAPHY 



The region here considered forms a small 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 physiographic regions 

 known as the Appalachian Region, the Piedmont Plateau, and the Coastal 

 Plain. These three districts follow the Atlantic border of the United 

 States in three belts of varying width from New England southwestward 

 to the Gulf states. 



The Appalachian Region extends from beyond the western limits of the 

 state eastward to the Blue Ridge and is divided into three districts known 

 as the Alleghany Plateau, the Greater Appalachian Valley, and the Blue 

 Ridge District. The first is west of the Alleghany Front and contains 

 rocks younger than Ordovician. Extending along the eastern border of 

 the Alleghany Front is the district known as the Greater Appalachian 

 Valley which admits of a twofold division into the zone of Alleghany 



