50 



Feather sionhaugli' s Geological Report, 



ghany mountain and Moshannon valley, in Centre county^ 

 Pennsylvania,"* notices the same " conglomerate rock or pud- 

 ding stone, composed of white quartz pebbles, set in a coarse 

 grit," as underlying the inferior beds of the bituminous coal 

 measures. 



The coal measures usually consist of repeated alternations 

 of micaceous sandstones in thick beds, or, when thinner, in 

 incoherent lamina, alternating with shales ; shales, beds of iron 

 stone, fire clay, bituminous coal, and occasional beds of lime- 

 stone. In these circumstances, the great coal fields of South 

 Wales, central England, northern England, Scotland, Ireland, 

 and the other great coal countries of Europe all agree. There 

 is perhaps not a section to be obtained from any mine in any 

 of these districts, for v/hich something like an equivalent could 

 not be found in the other districts, as to their general approxi- 

 mating character. The veins vary in width, from seams of a 

 minute proportionate part of an inch to upwards of thirty feet, 

 and, together with the veins of iron stone and argillaceous iron 

 ores, constitute, as is generally known, a most important part 

 of the wealth of the British empire. The structure of the 

 Western bituminous coal measures of the United States re- 

 sembles closely those of Europe, except in the circumstance 

 that they are not so much dislocated by disturbances from 

 below ; and one of the objects of this sketch of the structure of 

 the geological column being principally to show the general 

 agreement in the order of succession of rocks in both hemis- 

 pheres, which the coal itself makes sufficiently manifest, I shall 

 defer the particular consideration of the coal measures of this 

 country to another part of this report. 



Being now arrived at the point where that deficiency in 

 the United States of no less than twenty-one important strata 

 of European rocks, estimated to contain a geological thickness 

 of 5,500 feet, commences, beginning with the Exeter red con» 



* Monthly American Journal of Geology and Natural Science, p. 433. 



