The following facts also give support to this opinion. In the cave of Gaylenreuth, a fissure of the third grotto, was the means, in 1784, of disclosing a new one, fifteen feet long and four broad, where the greatest quantity of hyena or lion bones were found. The aperture was much too small for these animals to have passed through it.
In a cave discovered in 1824, in the district of Lanark in Upper Canada, Mr Bigsby observed, that the floor was covered with debris of brown granular limestone, similar to that of the walls, and that the bones especially formed a heap there. He thinks that the animal, whose bones have been found in this cave, was much too large to have got into it alive or entire.—Silliman’s Journal, June 1825, p. 354.
It must therefore be also admitted here, either that the bones could only have got into the cave in the same manner as the heaps of blocks found in the Adelsberg cave; that is to say, by falling from the roof, or that the apertures have been closed since the period at which the animals were buried.
If it be now considered, 1st, That the surface of the secondary limestone mountains of Carniola is covered with a layer of reddish clay; and, 2dly, That the clayey mud of the heap in the Adelsberg cave is mineralogically the same as that which forms the floor of the cave; may it not be supposed, that the same catastrophe which produced the heaps in the cave may have, at the same time, introduced into it the reddish clayey mud of the surface, which, by extending itself over the floor of the cave, would have contributed to cover the bones that were lying there?
Moreover, may it not have been the case, that, after the caves had been inhabited by the carnivorous animals, the substances falling from above, and coming from the surface of the soil, may have carried along with the clayey mud and the bones of bears, the spoils of large herbivorous animals, which they may have met with, and which cannot be supposed to have sought refuge in these caves during life.
There will, no doubt, be objected to me, that opinion which maintains, that the bones of herbivora have been dragged into the caves by the carnivorous animals. This might certainly have been the case with regard to small species, but it is not probable that the bones of large species could have been introduced in the same manner.
Admitting as certain, at least with regard to the Adelsberg cave, that the limestone blocks and the bear bones which accompany them, have fallen from the ceiling, the phenomenon of caves containing bones would connect itself pretty well with that of osseous brecciæ in a geological point of view. As M. Cuvier observes, “The nature of the rocks which contains the one and the other is not very different; and, besides, the fissures of caves being generally pretty wide, the bones would not have stuck, but would have fallen to the bottom, while those of the osseous brecciæ being much narrower, and not so deep, would have retained the bones at no great distance from the surface of the soil.”
Thus, from the facts observed in the caves of Germany and England, and from that of the Adelsberg cave, which I have described above, we may conclude, 1st, That the presence of bones in caves has been produced at two different periods, which, without doubt, have not been very distant from each other; the first, that when the animals inhabited these caves; the other, that when they had been transported there by a somewhat general catastrophe; 2dly, That the second epoch was contemporaneous with the osseous brecciæ, and was produced, like them, by a phenomenon or process of filling up.