ee ee ee a a O OEN? 
’ 
THE 
AMERICAN NATURALIST. 
VoL xvu. — JANUARY, 1883. — No. I. 
THE HISTORY OF ANTHRACITE COAL IN NA- 
TURE AND ART. 
BY JAMES S. LIPPINCOTT. 
HAT our anthracite has been debituminized is evident, but 
whence the heat that has thus changed its character is not so 
clear. It appears, says Dana, that the change has arisen from 
some cause connected with the uplifting of the rocks which con- 
tain the coal. In the anthracite fields the coal beds have been 
violently contorted, and the angles of dip are frequently vertical, © 
and in some instances the beds have been entirely inverted. This 
is doubtless due to the corrugations of the coating crust of the 
earth which, from some cause, has operated more violently in the 
eastern than in the western section of the coal basins. The an- 
thracite beds lie in closer proximity to the granite and gneissic 
bases of the Silurian rocks which form the lower substratum of 
the base of the coal rocks and thus were more fully exposed to 
the heating action of the earth’s nucleus, and more completely 
debituminized. The pressure of the vast accumulation of super- 
incumbent rocks must not be disregarded as a probable source of 
heat, and consequent chemical change. Under the influence of 
the elevated temperature and the great pressure which prevail at 
considerable depths, sedimentary rocks which have been long 
accumulating, would acquire a certain degree of fluidity and ap- 
proach a temperature nearly equal to that of redness, and thus 
we may find a cause adequate to debituminize the bituminous 
coals into the hardest anthracites. 
The more closely the coal strata are studied, the more forcible 
‘becomes the evidence that they aai in the manner of mod- 
VOL, XVII.—NO,. I. 
