CHAPTER XXVII 



THE PERMIAN PERIOD 



The name Permian was given by Murchison in 1841 to a series 

 of rocks which are very extensively developed in the province of 

 Perm in Russia. In North America the Permian followed upon 

 the Carboniferous with hardly a break, so that the distinction 

 between the two systems must be made entirely upon the fossils, 

 which change very gradually, by drawing a somewhat arbitrary 

 line of demarcation. In consequence, many geologists, especially 

 in this country, regard the Permian as a mere subdivision of the 

 Carboniferous. Its relations with the overlying Triassic system 

 are, however, nearly as close, and by some authorities it has been 

 referred to the latter. The Permian is, on the whole, distinctively 

 Palaeozoic, but it has several features which mark it out as transi- 

 tional to the Mesozoic. 



Texas Pennsylvania 



P • f Upp er Series. Double Mountain Beds. 



c . \ Middle Series. Clear Fork Beds. 



System. | 



[ Lower Series. Wichita Beds. Upper Barren Measures. 



Distribution of Permian Rocks 



American. — Toward the end of the Carboniferous there was in 

 the low-lying Appalachian coal field a slowly progressive move- 

 ment of elevation, resulting in the draining and drying up of most 

 of the region over which the peat bogs had been extended. The 

 movement spread east, north, and south, leaving in the middle of 

 the region a smaller area in which the conditions of the coal 

 measures continued very much as before. In the northern part 

 of the Acadian province Permian beds overlie the coal measures 



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