ORIGIN OF THE PENNSYLVANIA ANTHRACITE. 683 



practically the same amount of volatile as is found in the same 

 coal near Pocahontas, Virginia, close to the great fault of Abbs 

 valley. 



But it is unnecessary to look to metamorphisrrr for an expla- 

 nation of the Pennsylvania anthracite ; at best, metamorphism is 

 an unsatisfactory explanation, because it is difficult to find evi- 

 dence that metamorphosing agencies have been in operation 

 there. One does not think of metamorphism when he finds in 

 the coal of a given bed a variation of five or ten per cent, of 

 volatile within short distances, or even when he finds, as in 

 Sullivan county of Pennsylvania, anthracite in one bench and 

 bituminous in another bench at the same opening. 



As was shown long ago by Bischof and others, anthracite can 

 be produced simply by continuation of the process whereby 

 vegetable matter is converted into bituminous coal — by continued 

 formation of carburetted hydrogen until the hydrogen has been 

 removed. Professor Lesley's ingenious suggestion that this can 

 go on more readily in the anthracite region than in the bituminous 

 areas, because of the difference in composition and condition of 

 the rocks, hardly suffices. If only the extremes of the series 

 were to be accounted for, and if all were confined to the anthra- 

 cite strip, it might be regarded as sufficient ; but all gradations 

 from rich caking coal to anthracite occur in the First bituminous 

 basin, where the rocks are comparatively undisturbed and con- 

 sist largely of argillaceous shale. Moreover, in a single colliery 

 within the Southern Anthracite field, one bench of the Mammoth 

 bed yields a more than semi-bituminous coal, while from another 

 is obtained almost the driest of anthracite. But an equally 

 serious objection is, that the coal must have been converted 

 finally before complete entombment, so that the effect of the 

 pressure would be to remove water and to solidify the coal. The 

 hardening of the coal was complete in the Broad Top field before 

 the Appalachian revolution occurred, for in the final folding the 

 coal, as shown in some mines, was broken into lenticular and 

 polished fragments precisely like those of the Utica shale within 

 the disturbed valley east from the Anthracite Strip. The Lara- 



