of Bitumens, and of Bituminous Shales, 163 
Although we have seen that the solid asphalts, which differ 
from petroleum in containing less hydrogen, and a portion of 
oxygen, have in most cases been directly formed from organic 
matters by a process analogous to that which yields coal and pe- 
troleum, it appears that the latter body, like other hydrocarbons, 
may gradually undergo an oxydizing process, which, by remov- 
ing hydrogen and adding oxygen, at last converts the liquid 
bitumen into substances having the characters of asphalt, of 
coal, or even of anthracite. Mr. Vanuxem in his Report on the 
Geology of New York (page 33) described many years since, by 
the name of anthracite, a substance which is found in the Calcif- 
erous sand-rock. It occurs in druses or cavities with crystals of 
quartz and calcite, and often assumes the form of drops or but- 
tons, showing, according to Mr. Vanuxem, that it must have 
' been introduced in.a liquid, or at least a plastic state, and have 
ter, which he regarded as water, and leaving after incineration 
but a small amount of ash 
in diameter, as on the island of Orleans, where a vein of it in 
shale would furnish several hundred pounds of the material, 
nd where, as elsewhere, it has been mistaken for coal. At 
t. 
Flavien it fills a vein of an inch or two in argillite; the walls of 
Copper-mine it fills irregular cracks and fissures, and sometimes 
forms masses se r. 
The matter from these different localities has a resinous lustre, 
'Ch passes into sub-metallic in some cases. Its color is jet 
Powder, which has been used as a pigment. It has a conchoidal 
a 
