210. Dr Hutton's theory is no where stronger, than in what relates to the elevation and inflection of the strata; points in which all others are so egregiously defective. The phenomena to be connected are here extremely various, and even in appearance contradictory: the horizontally of one part of the strata; the inclined or vertical position of another; the perfect planes in which one set are extended; the breaking and dislocation found in a second; the inflection and sinuosity of a third; and almost every where the utmost rigidity and induration, combined with appearances of the greatest softness and flexibility; the preservation of a parallelism of superficies in the midst of so much irregularity, and the assumption of a determinate species of curvature, under circumstances the most dissimilar; all these appearances were to be connected with one another, and with the consolidation of the strata, and this is done by the twofold hypothesis, of aqueous deposition, and the action of subterraneous heat. When these circumstances are fairly considered, and when the shifts which other systems are put to on this occasion are remembered, I think it will be granted, that few attempts at generalization have been more successful, than that which has been made by the Huttonian Theory. 211. To the fact of the elevation of the strata, the study of geology is much indebted. The stratified form of a great proportion of the earth's surface, gives to minerals that organization and regularity, which makes their disposition an object of science, and their inclined position serves to bring that organization into view, from far greater depths than we can ever reach by artificial excavations. If, for instance, the termination of strata, that make with the horizon an angle of 30°, lying one over another, is seen for a horizontal distance of two miles; then it is certain, that if these strata have that extent under ground, which may be reasonably supposed, the thickness of the whole mass, measured by a line perpendicular to its stratification, is half the horizontal distance, or amounts to one mile. It would also require a pit to be sunk from the uppermost of these strata, to the depth of (2 miles × tan 30°, =) 6093 feet before it could intersect the undermost; and therefore, if we suppose the same stratum to preserve the same character for the extent of some miles, we obtain the same information from inspecting the edge-seams, and see in reality as far into the bowels of the earth, as if we had sunk a perpendicular shaft to the depth of 6000 feet.