FORMATIONS AND PHYSICAL HISTORY 



445 



limited by the overlap of younger f or- 

 ations. Except in Arkansas and Okla- 

 homa, \\here the strata are folded, the 

 Coal Measures of this area are nearly 

 orizontal. 



(6) The Nova Scotia- New Brunswick 

 al-field, on either side of the Bay of 

 Fundy, contains an area of about 18,000 

 square miles. The coal is bituminous, of 

 ;ood quality. 



Non-productive areas. In the vicinity 

 f Narragansett Bay, the Carboniferous 

 system has great thickness, and locally 

 rests on beds of Cambrian age. Coal 

 >ccurs here, but it is too highly anthracitic 

 (or graphitic) to burn readily. The beds 

 are much deformed and are associated 

 with igneous rocks. Carboniferous rocks 

 occur at other points in New England, 

 here they are partly igneous (Fig. 389) 

 r meta-igneous, and partly meta-sedi- 

 entary. 



West of the Great Plains. The system 

 widespread west of the Great Plains, 

 nd probably underlies the Plains them- 

 Ives. With rare exceptions, the western 

 s are coal-less, the abundant coal of 

 at region belonging to later systems. 

 he coal-less phase of the system, the 

 hole earth considered, is far more wide- 

 pread than the coal-bearing. 



In some parts of the west, the Car- 

 niferous system includes formations 

 hich resemble the "Red Beds" of the 

 ext (Permian) system. This is the case 

 the southern part of the Rocky Moun- 

 tain region, and in the plains adjacent, and 

 here the separation of the Pennsylvanian 

 system from the Permian is not very dis- 

 tinct, or has not been carefully worked out. 



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