GENERAL OBSERVATIONS. 



403 



5. Complete extermination of the Carboniferous life. — At the close 

 of the Carboniferous age there was a complete extermination of all 

 living species. No plant or animal of America continues from the 

 Carboniferous into the Eeptilian age ; and the same is probably- 

 true for EurojDe. 



DISTUEBANCES CLOSING PALEOZOIC TIME. 



1. AMERICAN. 



After the long ages of comparative quiet, when the successive 

 Paheozoic formations were in slow progress, and finally the rock- 

 foundation of the continent east of the Rocky Mountains was nearly 

 completed, a change of great magnitude began, which involved the 

 Appalachian region with the continental border adjoining, and well 

 merits the title of the Appalachian revolution. 



The evidences of the change may be treated of under two heads: — 

 1, disturbances of the strata ; 2, alteration or metamorphism, due, 

 partly at least, to heat. 



1. Disturbances of the strata. 



1. Flexures. — The Coal measures of Pennsylvania, Ehode Island, 

 and Nova Scotia, which were originally spread out in horizontal 

 beds of great extent, are now tilted at various angles, or rise into 

 folds, and the strata are broken and faulted on a grand scale. The 

 folds vary from a few rods to one hundred or more miles in breadth, 

 and are in many successions over the region, wave succeeding wave. 

 Moreover, not only the Coal measures, but the Devonian and Silu- 

 rian, and in some regions, at least, part of the Azoic beds beneath, 

 are involved together in this majestic system of displacements. 

 The following facts on this subject are mainly from the Memoirs 

 and Geological Eeports of the Professors Eogers. 



Fig. 619. 



Section of the Coal measures, near Nesquehoning, Pa. 



The general character of the flexures is illustrated in the annexed 

 sections. Fig. 619 (by Taylor) is from the anthracite strata of the 



