' 
S. FE. Peckham—The Origin of Bitumens. es 
It is not necessary here to discuss the nature or origin of 
metamorphic action. It is sufficient for our purpos 
that from the Upper Silurian to the close of the Carboniferous 
period the currents of the primeval ocean were transporting 
sediments from northeast to southwest, sorting them into 
gravel, sand and clay, forming gravel bars and great sand beds 
beneath the ripples, and clay banks in still waters, burying 
vast accumulations of sea weeds and sea animals far beneath the 
surface, The alteration due to the combined action of heat, 
steam and pressure, that involved the formations of the Appa- 
lachian system, from Point Gaspé in Canada, to Lookout 
Mountain, in Tennessee, including the Carboniferous and ear- 
lier strata, distorting and folding them, converting the coal 
into anthracite and the clays into crystalline schists, ela 
their eastern border, could not have ceased to act westwar 
action to a greater or less degree, and that “chronic evapora- 
tion” of Professor Lesley must have been the inevitable conse- 
uence. 
Too little is known about petroleum at this time to enable 
any one to explain all the phenomena attending the occurrence 
of petroleum, upon any hypothesis; but it seems to me that the 
different varieties of petroleum, from Franklin dark oil near 
the surface, to Bradford and Clarendon amber oil far beneath 
the surface, are the products of fractional distillation; and one 
of the strongest proofs of this hypothesis is found in the large 
content of paraffine in the Bradford oil under the enormous 
_pressure to which it is subjected. So, too, the great pools of 
“oil in southern Kentucky are without doubt distilled from the 
geode cavities beneath and concentrated in fissures of the 
rocks near the surface. 
If this hypothesis, which embraces all of the facts that have 
thus far come within my knowledge, really represents the 
operations of nature, then we must seek the evidences of heat 
action at a depth far below the unaltered rocks in which the 
petroleum is now stored. We ought to expect to find the coal 
In its normal condition. We should not expect to find the 
carbonized remains of organisms in the rocks containing the 
petroleum. As the metamorphic action took place subsequent 
to the Carboniferous era, we should expect to find the porous 
sandstones of that formation in certain localities saturated with 
