contains. A range of limestone rock 100 miles in length by 10 miles in
width, and 1,000 yards in depth, would contain 743,000 million tons of
carbon, or sufficient to provide carbon for 875,000 million tons of
petroleum. Deposits of oil-bearing shale have also limestone close at
hand; e.g., coral rag underlies Kimmeridge clay, as it also underlies
the famous black shale in Kentucky, which is extraordinarily rich in
oil.

II. As evidence of volcanic action in close proximity to petroleum
strata, the mud volcanoes at Baku and in Burma are described, and a
sulphur mine in Spain is mentioned (with which the writer is well
acquainted), situated near an extinct volcano, where a perpetual gas
flame in a neighboring chapel and other symptoms indicate that
petroleum is not far off. While engaged in studying the geological
conditions of this mine, the author observed that Dr. Christoff
Bischoff records in his writings that he had produced sulphur in his
own laboratory by passing hot volcanic gases through chalk, which,
when expressed in a chemical formula, leads at once to the postulate
that, in addition to sulphur, _ethylene_, and all its homologues
(C_{n}H_{2n}), which are the oils predominating at Baku, would be
produced by treating:

2, 3, 4, 5 equivs. of carbonate of lime (limestone) with
2, 3, 4, 5 " sulphurous acid (SO_{2}) and
4, 6, 8, 10 " sulphureted hydrogen (H_{2}S);

and that marsh gas and its homologues, which are the oils
predominating in Pennsylvania, would be produced by treating:

1, 2, 3, 4, 5 equivs. of carbonate of lime with