tible, like those of our springs, of being refilled, as the springs are kept full of water by the penetration from the surface.
If, then, we put aside the eruptive process as not well founded, it follows that the search for petroleum should be made with account taken of the conditions of formation of the sedimentary beds, of the extension of the basins in which they are deposited, and of the formations over them.
While the natural hydrocarbons are indisputably found in the sedimentary beds, from the most ancient to those which are still in process of formation, it is nevertheless certain that so far they are most extensive and most generally distributed in the Tertiary formations—excepting always the Silurian and Devonian deposits of North America, which were formed under geophysical conditions which have not yet been recognized in other regions where formations of the same age exist.
In a general way, the signs of the existence of solid, liquid, or gaseous hydrocarbons, exhibited by mud volcanoes, disengagements of natural gas, etc., authorize the presumption of beds near the surface, so that it is useless in such cases to anticipate a favorable result from deep borings.
All the facts noted by students of the natural hydrocarbons may be explained without difficulty under the hypothesis of the organic origin of the natural hydrocarbons, which becomes a complete system, the value of which imposes itself upon every one seeking the solution of the question. All is easy of conception if we suppose a simultaneous precipitation of mineral matters and organic substances derived from the decomposition of animals and plants, when these are found in suitable conditions of the medium and of their own being at the moment they are buried. But all becomes obscure and inexplicable under the hypothesis that these substances are formed in the depths of the globe under the influence of a high temperature and considerable pressure.
