But the cavern inscriptions make it as certain as can be that the rate of speed here allowed for the formation of stalagmite is vastly too high, and therefore that the time allowed for the formation is vastly too low. The famous inscription of 1688 was shown to me a few days back[56]. It was at that very time wet with the drip from the cavern roof, a drip falling at the rate of thirty-four drops a minute. If the date were really cut in the year 1688 (and there is no reason to suppose that it was not), by our first calculation more than two inches of stalagmite ought to have formed over it. Instead of which there is but a thin veneer, a veneer that was observed upon it more than forty years ago, and which has not in all those forty years increased enough to make such a description of it inappropriate. If the date 1615 be authentic, over which, in the opinion of the superintendents of the exploration, not one-eighth of an inch of stalagmite has been formed in more than two centuries and a-half, at the same rate of progression twelve feet and a-half of stalagmite would demand for its formation three hundred thousand years. This cavern by itself, therefore--this one little crack in the outermost rind of the earth’s surface--proves a comparatively immense antiquity for the existence of organic life and of human beings upon the globe. But to compare the antiquity of the cavern contents with the antiquity of the limestone formation in which they are contained is positively beyond any intelligible numerical measurement. Yet the limestone formation itself is filled with the relics of living creatures, and in some parts, if not in all, is one gigantic mass of such remains.