94 



STRUCTURAL GEOLOGY OF NORTH AMERICA 

 APPALACHIAN PLATEAU 



Hudson, R. 



Fig. 7.3. Block diagram of the geomorphic provinces of the central Appalachians and the 

 Atlantic Coastal Plain, reproduced from Johnson, Bascom, and Sharp, 1933. M, Manhattan; 

 Sb, Stroudsburg; P. Pottsville; R, Reading; Hb, Harrisburg; CI, Carlisle G, Gettysburg; Ch, 



around it in successive elliptical zones are the Monongahela ("upper 

 productive"), Conemaugh ("lower barren"), Allegheny ("lower produc- 

 tive"), and finally the fairly thin Pottsville. Most of the limestone and 

 the best coal beds are in the Monongahela formation. 



Chambersburg; Mr, Mercersburg; H, Hagerstown; HF, Harpers Ferry; F, Frederick; Rv, Rock- 

 ville; Wash, Washington; Bal, Baltimore; Phil, Philadelphia; Tr, Trenton. 



The Allegheny plateau is continuous with the Cumberland plateau, and 

 any boundary is arbitrary. The southern plateau is somewhat less dis- 

 sected, and the nearly flat-lying strata are largely the sandstones, shales, 

 and basal conglomerates of the Pottsville formation. 



