red sandstone which lies over it, certain new beds are found, which fill up the incoherent interval; which offer the same evidence as the strata below and above them, of having been produced tranquilly; and which do not violently differ in position from either group. The appearance of incoherence in the series arose from the occurrence, in the region first examined, of a gap, which is here filled up,--a blank which is here supplied. Hence it is inferred, that whatever of violence and extreme disturbance is indicated by the dislocations and ruins there observed, was local and partial only; and that, at the very time when these fragmentary beds, void of organized beings, were forming in one place, there were, at the same time, going on, in another part of the earth's surface, not far removed, the processes of the life, death and imbedding of species, as tranquilly as at any other period. And the same assertion is made with regard to the more general fact, before described, of the stratigraphical constitution of mountain chains. It is asserted that the unconformable relation of the strata which compose the different parts of those chains, is a local occurrence only; and that the same strata, if followed into other regions, are found conformable to each other; or are reduced to a virtually continuous scheme, by the interpolation of other strata, which make a transition, in which no evidence of exceptional violence appears. 25. We shall not attempt (it is not at all necessary for us to do so) to decide between the doctrines of the two geological schools which thus stand in this opposition to each other. But it will be useful to our argument to state somewhat further the opinions of this latter school on one main point. We must explain the view which these geologists take of the mode of succession of one group of _organized_ beings to another; by which, as we have said, the different successive strata are characterized. Such a phenomenon, it would at first seem, cannot be brought within the ordinary rules of the existing state of things. The species of plants and animals which inhabit the earth, do not change from age to age; they are the same in modern times, as they were in the most remote antiquity, of which we have any record. The dogs and horses, sheep and cattle, lions and wolves, eagles and swallows, corn and vines, oaks and cedars, which occupy the earth now, are not, we have the strongest reasons to believe, essentially different now from what they were in the earliest ages. At least, if one or two species have disappeared, no new species have come into existence. We cannot conceive a greater violation of the known laws of nature, than that such an event as the appearance of a new species should have occurred. Even those who hold the uniformity of the mechanical changes of the earth, and of the rate of change, from age to age, and from one geological period to another; must still, it would seem, allow that the zoological and