Eastern North America. 



403 



The geologist sees and describes the orogenies, and he 

 often measures the height of the mountains from their 

 internal structure, and their geographic extent either 

 from their actual presence or from their roots as now pre- 

 served in the structure of the earth. The stratigrapher, 

 however, sees yet other mountains reflected in the sedi- 

 ments, the sites of which may never be discovered. 

 Surely when we see more than 10,000 feet of Upper De- 



Fig. 6. — Orogenic provinces in eastern ^orth America. 



vonian marine sediments piled up in eastern Pennsyl- 

 vania, with a rapidly increasing accumulation of detritals 

 beginning in Hamilton time, we are justified in postulat- 

 ing a region of orogeny to the eastward in Appalachia, 

 and of the time of the crescendo of deposition (see Fig. 

 6). The proof that long rivers brought this sediment 

 from a mountainous area that lay to the east and north- 

 east is seen in the internal structure of the White Moun- 

 tains of New England, the Monteregian hills of Quebec, 



