XIII. On the Origin of Petroleum

Abstract

In the opening of his paper, the author alluded to the different theories which had been propounded by geologists on the subject. There was, first, the distillation theory, that petroleum has been produced by the slow distillation, at low temperature, of coal and other bituminous substances within the earth. Next was the theory which supposed petroleum to have been produced from decayed vegetable matter by a process similar to that by which coal was formerly supposed to have been formed, viz., by the mineralisation of woody fibre which evolves marsh gas, carbonic acid, and water. The next notable theory was that petroleum in many cases must have been of animal origin, from the fact of its being found in the lower palaeozoic strata, which contain no traces of land plants. Then there was Mr. Wall’s “special mineralisation” theory, that bituminous matter has proceeded from vegetable remains which have undergone a special mineralisation, not attributable to heat, nor of the nature of a distillation, but due to chemical reaction at the ordinary temperature, and under normal conditions of climate. The author then proceeded to state some of the difficulties attaching to each of these theories as a solution of the problem of the origin of petroleum. These difficulties seemed to him too great for geologists themselves to clear away, and he believed it was only when geology was studied side by side with chemistry that anything like a satisfactory conclusion on the subject could be arrived at. The first difficulty which