Observations on the Occurrence of Anthracite. — Gresley. 11 
creating anticline? which have their steeper slopes facing the 
west, as is found to be the case, 
14. The cooling off of the strata and the deep-seated or 
elevating pressures combined, would produce the jointing. 
Assuring, and all the observed slip-cleavage in the coal, etc. 
Such then, is about the best or briefest description the 
author can give of the successive geologic events to which 
the anthracite in Pennsylvania is probably mainly due, and 
upon which we would look back as having brought this splen- 
did fuel within our reach ; for had the Coal Measures remained 
down there in plutonic regions, where the anthraciting pro- 
cess went on, the probabilities are man would have been unable 
to reach it. This coal then I claim, is essentially a product of 
the origin, cause, and process of mountain-making, i. e. inter- 
nal heat acting upon water-soaked strata of vegetable matter 
and inorganic sediments, depressed far enough below the 
surface (prior to a necessary upheaval) to put the rocks 
through a process of " cooking" ; which process of course 
operated more or less according to depth, kind, and amount 
of water, the variable character of the indivdual beds and 
local influences. Thus we find this anthracite is associated 
with the remnants of high mountains, composed of a great 
thickness of sedimentary rocks ; the coal-seams being accom- 
panied by sandjr and pebbly strata originally filled with water, 
which water, on becoming heated, and kept hot long enough, 
was principally instrumental in changing the once bitumin- 
ous coal into semi-anthracite and pure anthracite. 
VI. Evidences of Former Hydrothermal Agency in the 
Region. 
So much then for the theory. We will next see if there is 
any evidence in the region that internal heat of the earth was 
an agent in anthracite making. American geologists have 
reported no less than 56 hot springs occurring on the strike of 
the folded and twisted strata passing through the antliracite 
regions. That the origin of the lead and zinc ores, alread}^ 
mentioned as occurring in the anthracite, may be ascribed to 
ascensional thermal waters seems reasonable.* 
♦"Genesis of Ore-Deposits." by F. Posepny in Trans. Am. Inst. M. 
E., 1893. 
