Beneath the level of this canal a shaft has been sunk through a grey argillaceous substance, called in this country clunch, which is said to be a pretty certain indication of coal; beneath this lies a stratum of coal, about two or three inches thick, of an inferior kind, yielding little flame in burning, and leaving much ashes; below this is a rock of a harder texture; and beneath this are found coals of an excellent quality; for the purpose of procuring which with greater facility the canal, or horizontal aperture, is now making into the mountain. July, 1788. Beneath these coals in some places is found salt water, in other parts of the adjacent country there are beds of iron-stone, which also contain some bitumen in a less fluid state, and which are about on a level with the new canal, into which the fossil tar oozes, as above described. There are many interesting circumstances attending the situation and accompaniments of this fountain of fossil tar, tending to develop the manner of its production. 1. As the canal passing into the mountain runs over the beds of coals, and under the reservoir of petroleum, it appears that a _natural distillation_ of this fossil in the bowels of the earth must have taken place at some early period of the world, similar to the artificial distillation of coal, which has many years been carried on in this place on a smaller scale above ground. When this reservoir of petroleum was cut into, the slowness of its exsudation into the canal was not only owing to its viscidity, but to the pressure of the atmosphere, or to the necessity there was that air should at the same time insinuate itself into the small cavities from which the petroleum descended. The existence of such a distillation at some antient time is confirmed by the thin stratum of coal beneath the canal, (which covers the hard rock,) having been deprived of its fossil oil, so as to burn without flame, and thus to have become a natural coak, or fossil charcoal, while the petroleum distilled from it is found in the cavities of the rock above it. There are appearances in other places, which favour this idea of the natural distillation of petroleum, thus at Matlock in Derbyshire a hard bitumen is found adhering to the spar in the clefts of the lime-rocks in the form of round drops about the size of peas; which could perhaps only be deposited there in that form by sublimation.