PEEMIAN AGE AND CLOSE OP THE PALJIOZOIC. 163 



latter liave been thrown into a series of folds , and the 

 topa of these folds have been more or less worn away 

 before the Permian beds were placed on them. But 

 if we pass on to the eastward, in the great plain 

 between the Yolga and the Ural mountains, where, in 

 the '' ancient kingdom of Perm,'' the greatest known 

 area of these rocks is found, an area equal in extent to 

 twice that of France, and which Sir R. I. Murchison, 

 who first proposed the name, took as the typical 

 district, we find, on the contrary, that the Permian and 

 Carboniferous are conformable to one another. If 

 now we cross the Atlantic and inquire how the case 

 stands in America, we shall find it precisely the same. 

 Here the great succession of earth- waves constituting 

 the Appalachian Mountains rises abruptly at the eastern 

 edge of the continent, and becomes flatter and flatter, 

 until, in the oroad plains west of the Mississippi, the 

 Permian beds appear, as in Russia, resting upon the 

 Carboniferous so quietly that it is not always easy to 

 draw a line of separation between them. As Dana 

 has remarked, we find at the western side of Europe 

 aud the eastern side of America, great disturbances 

 inaugurating the Permian period ; and in the interior 

 of both, in the plains between the Volga and the Ural 

 in one, and between the Mississippi and Rocky Moun- 

 tains in the other, an entire absence of these disturb- 

 ances. The main difference is, that in eastern America 

 the whole Carboniferous areas have apparently been so 

 raised up that little Permian was deposited on them, 

 wh^e in Europe considerable patches of the disturbed 



