426 TRANSACTIONS OF THE AMERICAN INSTITUTE. 



found in the coal formation of North Carolina, were of igneous 

 origin, being protruded in a liquid state, like lava, from the 

 molten mass beneath. 



Mr. Nash, as he proceeded, pointed out the metallic substances 

 ■which accompanied, and were characteristic of the several forma- 

 tions. 



Dr. Stevens said, that in the coal basin of Deep river, in North 

 Carolina, anthracite coal is found in the immediate neighborhood 

 of the trap-rock; but, as you leave the trap-rock, the anthracite 

 changes its character, yard by yard, until it entirely disappears, 

 and nothing but bituminous coal is found. 



Mr. Nash belongs to a different school of geology from myself, 

 and we explain things quite differently. There is a conglomerate 

 rock, called the coal conglomerate, because it always underlies 

 the true coal formation of the United States. On the eastern 

 side of the great coal barrier, this stratum of conglomerate rock 

 may be 1,000 or 1,200 feet thick; but, mile by mile, as you 

 proceed in a northwestern direction, it turns out, so that at 

 Cuyahoga it is only about 80 feet thick. This conglomerate may 

 always be known from its containing certain fossils, certain sea 

 shells. Rising twenty to forty feet above the conglomerate rock, 

 in the Lehigh coal basin, you come to a bed of coal three feet 

 thick. If the coal is turned over, the conglomerate is found to 

 be turned over with it. This vein of coal contains certain fossils. 

 In the United States some 150 species of trees and plants have 

 been found associated with our coal. These fossils are never 

 confounded. The fossils, in different layers, are always distinct 

 from each other. Follow the beds westward and you find them 

 still holding the same relation to each other, although thinner ; 

 and we infer that the anthracite, the semi-bituminous, and the 

 bituminous coals were originally one formation. As we travel 

 eastward from Cu^^ahoga, we pass over the whole outcrop of the 

 appalochean coal system. We find the conglomerate rock at 

 Cuyahoga Falls, and a little south of it the first bed of coal, 

 which is the coal used in Cleveland and upon Lake Erie. There 

 are a series of eight beds of coal coming to the surface succes- 

 sively as you proceed towards the Ohio river. These beds of 

 coal are all known and have all been worked between Cleveland 

 and the Ohio river. They are all bituminous. Above these 

 comes a barren stratum, and then three upper layers of coal. 

 The lower of the three is the Pittsburg seam; the next is the 



