Page:Quarterly Journal of the Geological Society of London, vol. 27.djvu/247

Rh had been found, but nothing else. But here again, as with the Red Crag, the cause of their non-discovery appears to have been that they are confined almost entirely to the basement-bed of both deposits, and this bed, in the Coralline Crag, as well as in the Red Crag, proves to consist chiefly of water- worn fragments and pebbles derived from older deposits. It was only at one small pit, and there for a short time, that the bed of phosphatic nodules at the base of the Coralline Crag was worked; and yet there were there found as many, or more, specimens than are usually found in Red-Crag workings of the same extent. The following species have been found:—Mastodon arvernensis, Rhinoceros (Schleiermacheri?), Cervus, Belemnoziphius, Baloena.

The large teeth of Carcharodon, the skull-bones of Belemnoziphius and the flat Cetacean bones are all drilled superficially by some boring animal. This must, in all probability, have been done before the bones were fossilized; and as the holes present mere segments of their original forms, either they may have been rolled and worn so as to reduce the thickness of the bone and so remove a portion of the drilled surface, as has been suggested, or else the bones may have been originally imbedded in some clays or marls through which boring shells may have drilled until, coming into contact with the harder bone, they merely impinged on its surface, which they failed to penetrate. Neither explanation, however, is satisfactory. In the one case, the bones have generally lost little or nothing of their substance, while the difficulty on the latter supposition is that many of these bones are drilled on all sides; one of the skulls of the Belemnoziphius, for example, shows traces of these holes on all its four surfaces, whereas, if the bone had been imbedded in clay or marl, we should have looked for perforations in one surface only.

The condition, in fact, of the bones at the base of this Crag is precisely of the same character as that of those at the base of the Red Crag. In both they are worn and mineralized. At the same time I think it not improbable that the Mastodon and the Rhinoceros may have lived at the Coralline-Crag period—though the general absence of all bones other than teeth, and the circumstance that the materials of the bed in which they occurred is so largely derivative, throw doubt on the whole collection generally. The Whale certainly lived at that period. The condition of many of the vertebrae, their distribution at various levels, and the occurrence, in one case, of seven vertebrae in connexion, show that this animal lived in the Coralline-Crag sea, as did probably some of the other Cetaceans.

From the preceding particulars of the fauna of the Coralline Crag, it would seem that the differences in the proportions of recent to extinct species in the different classes is so great that I do not see how the results are at present to be reconciled. As with the Mollusca, however, I think it extremely probable that the other groups will, after we know more of their distribution in the greater depths of the Atlantic, be found to require considerable revision. In the