Consistently with this view of things, the strata or regular solid parts, under the soil or travelled earth, should be found in some shape corresponding to the represented state of those things, when affected by the powers which have acted upon the surface of the earth. Here, accordingly, the strata are always to be observed with those marks of resolution, of fracture, and of separation, which have most evidently arisen from the joint operation of those several causes that have been now explained. But though every operation of the globe be necessarily required for the explanation of those appearances which we now examine, it is principally the action of the sun and atmosphere, and the operations of the waters flooding the surface of the earth, that form the proper subject of the present investigation.
It must not be imagined that, from the present state of things, we may be always able to explain every particular appearance of this kind which occurs; for example, why upon an eminence, or the summit of a ridge of land which declines on every side, an enormous mass of travelled soil appears; or why in other places, where the immediate cause is equally unseen, the solid strata should be exposed almost naked to our view. We know the agents which nature has employed for those purposes; we know the operations in which the solid parts are rendered soil of various qualities and for different purposes; and when we find the marks of those natural operations in places where, according to the present circumstances, the proper agents could not have acted or existed, we are hereby constrained to believe, that the circumstances of those places have been changed, while the operations of nature are the same.
It is thus that we shall find reason to conclude an immense period of time, in those operations which are measured by the depradations of water acting upon the surface of the earth; a period however which is to be esteemed a little thing compared with that in which a continent had taken birth and gone into decay; but a period which interests us the more to examine, in that it approaches nearer to another period, for the estimation of which _some data_ may perhaps be found by naturalists and antiquaries, when their researches shall be turned to this subject. It is only in this manner that there is any reasonable prospect of forming some sort of calculation concerning that elapsed time in which the present earth was formed, a thing which from our present data we have considered as indefinite.