168 T. Sterry Hunt on the Chemical and Geological History 
appears not only destitute of petroleum, but from the water, by 
which it is impregnated, to be impermeable to it. In some of 
which forms the matrix of the corals, and resembles in texture 
the associated beds. As the fractured surfaces of the oil-bearing 
beds become dry, the oil spreads over them, and thus gives rise 
to the appearance of a continuous band of dark oil-stained rock, 
limited above and below by the lighter limestone, from which, 
however, it is separated by no-planes of bedding. The layer of 
three inches was seen to be twice interrupted in an exposure of 
a few feet, thus presenting lenticular beds of the oil-bearing 
rock. Besides the occasional specimens of Heliophylium without 
oil, disseminated in the massive limestone, a thin and continu 
ous bed of Favosites is met with, which is white, porous, and 
free from oil, although beds both above and below are filled with 
it. It is from the weathered outcrop of one of these that was 0b 
tained the specimen already described on page 164, in the cells 
of which was found the infusible and insoluble product of t 
oxydation of petroleum. When the oil-bearing beds are exposed 
in working the rock, the oil flows out and collects upon the water 
of the quarry. Besides the two beds noticed above, there are 
said to be others, which were concealed by water at the time of 
my visit. The facts observed at this locality appear to show 
that the petroleum, or the substance which has given rise to 
was deposited in the beds in which it is now found, at the for 
mation of the rock. We may suppose in these oil-bearing De 
an accumulation of organic matters, whose decomposition, 12 
the midst of a marine calcareous deposit, has resulted in thelf 
complete transformation into petroleum, which has found & 
lodgement in the cavities of the shells and corals immediately 
near. Its absence from the unfilled cells of corals, in the @ sf 
of the oil into these strata either by distillation or by infiltratio™ 
he same observations apply to the petroleum of the i, 
limestone, and if it shall hereafter be shown that the source ’ 
Fe Reap (as distinguished from asphalt) in other regions, 8 » 
be found in marine fossiliferous limestones, a step will have bee? 
