106 S. F. Peckham—The Origin of Bitumens. 
their views upon extended observations in Canada, West Vir- 
ginia and Kentucky. At several localities in Can ada, Dr. 
Hunt has observed the marine fossils of the Trenton limestone 
filled with petroleum in'which it was hermetically sealed, 
and he regards the petroleum that saturates portions of the 
hese limestone near Chicago, as cigenous to that forma- 
n a recent letter, J. "M. Safford informs me that in 
ee limestone rocks that form the Silurian basin of middle 
Tennessee it is not uncommon to ‘aad with gente cavities 
lined with calcite crystals and containing more or less petro- 
dw 
‘leum. Iam also informed by ard Bei that ‘te Clinton 
limestone of Ohio, ye over the whole northern border of 
ties. esley’s paper on “the existence of petroleum 
in the autre coal field of Kentucky,” he has shown that 
in Johnson County, Kentucky, the great Carboniferous con- 
glomerate is saturated with petroleum at horizons now above 
the level of the water in the streams that intersect the coun- 
try. He thinks the Coal-measure plants contributed to the 
formation of the petroleum and observes that ‘the specifi¢ 
gravities of the oil, decreasing with the increase of the depth, 
is a fact which shows conclusively that a chronic evaporation 
or distillation of the whole mass of oil in the crust of the earth 
within reasonable reach of the surface), has always been and 
is still going on, converting the animal and plant remains into 
ae oils, the habe oils into paged om the heavy oils into 
marks of which.are so infinitely numerous in the rocks, and 
with the infinitude of corralloid sea animals, the skeletons of 
which make up a ee part of the limestone pecans which 
of Wall in Trinidad appear to establish beyond a doubt that 
_the bitumen of that locality has been and is being produced 
eae 
Be ee eet ue a Te ae se ae 
ete 
at 
See opi ge ee Aen ame 
Pre 
pha <li oe Nir sete A pig: 
CREED STEEP at ne at, EEN MY SAME ee te 
ae eee ve 
neon ee 
So pee ie 
Peal aes 
. i 
Speck 
ye, 
ne 
