8 The Americini Geologist. July, 1896 
pile of the Coal Measures of the region are metamorphosed 
though not to the same extent, tlie contained coal in all its 
forms and at all horizons is more or less metamorphosed. The 
origin of the anthracite of Pennsylvania then was certainly 
a metamorphic one ; and not due or confined only to the certain 
horizons — the beds of coal — as Stevenson seems to suggest. 
The writer does not agree with those who suppose that the 
metamorphism apparent in the eastern Allegheny coal fields 
was principally a result of folding, crushing, thrust-pressures 
and of fissuring, which aided the escape of the volatiles of 
the coal ; but he would venture to submit what he will call 
the hot water or hydrothermal theory, as ])Ossibly the most 
rational one yet advanced, or the one to which all the observed 
facts or phenomena of the region in Pennsylvania (and certain 
others besides) fit best. By hot water he does not mean to 
suggest that the Coal Measures and the coal seams were de- 
posited in thermal waters, but that heated waters subsequently 
were instrumental in doing most of the observable metamor- 
phism in a manner to be presently indicated. 
V. Sequence of Geological Events Producing Pennsyl- 
vania Anthracite. 
This theory will merely be^ stated generally or by w^ay of 
a formal or working hypothesis, based on lines as broad as 
possible and compatible with the most recently advanced views 
bearing upon the fundamental and essential points in this 
connection. Attention is therefore directed to: 
1. The Pennsylvania anthracite fields or basins, as is well 
known, consist of a rudely parallel series of plicated canoe- 
shaped troughs lying in still larger similarly shaped synclines 
of Sub-C'arboniferous rocks of vast thickness (4,000 to 5,000 
feet says Dana) and forming part of a series of very thick 
strata (30,000 feet) of still older formations now involved in 
the general elevated mountain chain of folded and crumpled 
rocks known as the Appalachian uplift. In reality the anthra- 
cite basins are outliers (or remnants of a once enormous coal 
region), which owe their preservation from total annihila- 
tion by denudation to their synclinal or pockety forms. 
2. There are remnants of what Avas probably a great thick- 
ness of Permo-Carboniferous rocks in the anthracite region. 
These occur near Wilkes-Barre atul near Pottsville, and 
