Obserrafioiis ou the Occurrence of Anthracite. — Gresley . 5 
hard and fast lines for establishing a terminology; so that, 
just as the coarser as well as the liner grained inorganic 
strata of anthracite coal areas are found to be semi-meta- 
niorphic in character, i. e. in a transition stage between 
what may be called normal Coal Measures and decidedly 
metamorphosed strata of similar chemical composition, so 
should the coal seams they inclose be also regarded as serai- 
metamorphosed. There is no escape from such a conclusion ; 
neither would there appear to be any necessity for investiga- 
tors to go out of their way to seek an opposite theory of the 
origin of anthracitification. The point that seems to have 
puzzled us hitherto in accounting satisfactorily for Pennsyl- 
vania anthracite is that the crumpling, twisting and compact- 
ing of the C'Oal Measures of that region were not sufficient to 
produce anthracite, or that the conversion of the originally 
soft and bituminous coal was accomplished before the great 
upthrust of the Allegheny mountains took place, of which 
change we possess evidence. 
4. Atithracite, other than in. seams^ in the Coal Pleasures of 
Penniiiilcania. Besides the regular or irregular seams of an- 
thracite coal in Pennsylvania the associated strata are rich in 
films or streaks of coal. These may or may not be detected 
as fossil bark of prostrate trees or in forms sutticiently defi- 
nite to determine their exact nature; such stray or pocket 
deposits are known to miners as stringers, pipes, seeds, 
nests, plies, streaks, etc. Now, these extraneous unimportant 
(commercially) masses of coal in the Pennsylvania anthracite 
regions are not bituminous coal but anthracitic. They are 
apparently just as pure anthracite as are the beds or seams 
between which they lie. If, therefore, Stevenson's theory be 
conceded as applicable to the thicker or regular beds of an- 
thracite, it must apply equally to these scattered lilmy patches 
of the same material not in contact with the seams of coal; 
in other words, if it were necessary for vegetable matter to 
be longer exposed prior to burial by sediment in order to be- 
come anthracized, then every individual streak or lamina of 
anthracite embedded in shale and sandstone and presumably 
of vegetable origin must have been longer exposed ere sealing 
down by mud and sand ensued. We cannot admit the one and 
exclude the other; the mere dimensifxis of the masses of coal 
