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Occasionally there occurs a mass of trap, which in stead of being superimposed on the strata, is placed laterally respecting them, or else covers, in one part, the same body to which, in another, it approximates in that manner. Examples of this occur in Sky and in Morven ; while a careful examination shows that the lateral approximation is an intersection ; so that the mass is, properly, a vein. These intersecting masses are often of enormous dimensions, extending even for miles ; and, like the smaller veins, they reach to unknown depths; probably forming a com munication between the overlying masses and bodies of similar or greater dimensions, situated beneath the strata. That such masses do exist beneath, as well as above the stratified rocks, is evinced by the circum stances often attending veins, were it not even a ne cessary inference from the general theory of their origin. In these cases, the intersected and bent or broken strata are also turned upwards, as if by a force acting from below; indicating the place of the parent mass and the progress of the intruding mate rial upwards. Bute presents an excellent example of this fact. In Sky and elsewhere, strata are also found bent over an interior or subjacent mass of trap, of inaccessible depth: displaying, distinctly, what the theory had inferred; while, in other instances, they have been broken as well as bent, so as to have given exit to the subjacent material. This particular modification is obviously analogous to the vases of granite, which trap resembles in so many other par ticulars ; and it has given rise to the inference for merly examined, that, in the predominant cases, it has been protruded from beneath in a liquid state ; being thus analogous to those products of volcanic eruption, with which its mineral characters correspond so nearly. VOL. II. K