44. Indeed, the interposition of a breccia between the primary and secondary strata, in which the fragments, whether round or angular, are always of the primary rock, is a fact so general, and the quantity of this breccia is often so great, that it leads to a conclusion more paradoxical than any of the preceding, but from which, nevertheless, it seems very difficult to withhold assent. Round gravel, when in great abundance, agreeably to a remark already made, must necessarily be considered as a production peculiar to the beds of rivers, or the shores of continents, and as hardly ever formed at great depths under the surface of the sea. It should seem, then, that the primary schistus, after attaining its erect position, had been raised up to the surface, where this gravel was formed; and from thence had been let down again to the depths of the ocean, where the secondary strata were deposited on it. Such alternate elevations and depressions of the bottom of the sea, however extraordinary they may seem, will appear to make a part of the system of the mineral kingdom, from other phenomena hereafter to be described. 45. On the whole, therefore, by comparing the actual position of the strata, their erectness, their curvature, the interruptions of their continuity, and the transverse stratification of the secondary in respect of the primary, with the regular and level situation which the same strata must have originally possessed, we have a complete demonstration of their having been disturbed, torn asunder, and moved angularly, by a force that has, in general, been directed from below upwards. In establishing this conclusion, we have reasoned more from the facts which relate to the _angular elevation_ of the strata, than from those which relate to their _absolute elevation_, or their translation to a greater distance from the centre of the earth. This has been done, because the appearances, which respect the absolute lifting up of the strata are more ambiguous than those, which respect the change of their angular position. The former might be accounted for, could they be separated from the latter, in two ways, viz. either by the retreat of the sea, or the raising up of the land; but the latter can be explained only in one way, and force us of necessity to acknowledge the existence of an expanding power, which has acted on the strata with incredible energy, and has been directed from the centre toward the circumference.