96 Horner's Geological Address, 



the following as an example of the almost boundless re- 

 sources of fuel which this country affords. At Brownsville, on 

 the Ohio, there is a seam, ten feet thick, of good bituminous 

 coal, commonly called the Pittsburg seam, which may be fol- 

 lowed the whole way to Pittsburg, fifty miles distant. " The 

 boundaries of this seam have been determined with consider- 

 able accuracy by the Professors Rogers in Pennsylvania, 

 Virginia, and Ohio ; and they have found the elliptical area 

 which it occupies to be 225 miles in its longest diameter, 

 while its maximum breadth is about 100 miles, giving a 

 superficial extent of about 14,000 square miles." 



Mr Lyell states that at Blossberg in Pennsylvania he was 

 much struck with the surprising analogy of the coal-measures 

 to those of Europe in mineral and fossil characters. The same 

 grits or sandstones are found as those used for building near 

 Edinburgh and Newcastle ; similar black shales occur, often 

 bituminous, with the leaves of ferns spread out as in a her- 

 barium, the species being for the most part identical with 

 British fossil plants ; there are seams of good bituminous 

 coal, some a few inches, others several yards, in thickness, 

 associated with beds and nodules of clay ironstone ; and the 

 whole series rests on a coarse grit and conglomerate, con- 

 taining quartz pebbles, very like our millstone grit. The 

 same similarity of mineral and fossil characters to European 

 coal-measures is found to prevail throughout North America. 

 That remarkable circumstance of the very general occurrence 

 of a sandy clay abounding in Stigmarise, beneath the seams of 

 <joal, observed in the Welsh and other coal-fields of Britain, 

 is also found to prevail in those of North America. Mr 

 Lyell saw numerous instances of this : thus, at Pottsville in 

 Pennsylvania, there are thirteen seams of anthracitic coal 

 (true bituminous coal supposed to be altered by metamorphic 

 action, a subject to which I shall allude hereafter), several 

 of them from eight to ten feet thick, and in a vertical posi- 

 tion : on the side which had been the roof of the coal, con- 

 sisting of shales, he observed numerous ferns with stems of 

 Sigillaria, Lepidodendron, and Calamites ; on the other side, 

 that which had once been the floor, he found an underclay 

 with numerous Stigmarise, often several yards, and even in 



