VALLEY OF TfTE MISSISSIPPI. 15 



tic casts, and vegetable impressions, likewise attend 

 the coal formations, and it is only the difference of 

 their elevation above the horizon which in any man- 

 ner distinguishes the same strata in one country from 

 those of the other. Here, however, the difference is 

 sufficiently obvious. In Derbyshire, and in every 

 other part of England of which I possess any know- 

 ledge, the beds of coal are never come at by any 

 thing like an horizontal drift ; indeed, the dip of 

 such strata is often but little inferior to that of the 

 primitive rocks, and expensive machinery is always 

 necessary, both to raise the coal and drain the mine. 

 In the western states of America, on the contrary, 

 the coal is obtained by an almost horizontal drift, 

 and draining becomes unnecessary. If we are 

 then to search for any transatlantic region simi- 

 lar in its materials and in their horizontal stratifica- 

 tion with the extensive plains of Ohio, of Michi- 

 gan, Indiana, Illinois, Kentucky, West Tennessee, 

 and a part of the territory of Missouri, it is to be 

 found in those extensive plains or steppes of the 

 Tartarian desert traversed by the Kuban, which 

 have been described by Professor Pallas and 

 Daniel Clarke. Here, 1 think, we find strata of the 

 same materials, at least, as it regards calcareous rock, 

 abounding with fossil reliquiae, and also as nearly ap- 

 proaching the horizontal level. As we pursue, 

 however, our enquiry concerning the western and 

 northern limits of this great calcareous platform, 

 through Canada, and the territories of Missouri and 



