405. The animal remains of the second class, are generally found in the neighbourhood of limestone strata, and are either enveloped or penetrated by calcareous, or sometimes ferruginous matter. Of this sort are the bones found in the rock of Gibraltar, and on the coast of Dalmatia. The latter are peculiarly marked for their number, and the extent of the country over which they are scattered, leaving it doubtful whether they are the work of successive ages, or of some sudden catastrophe that has assembled in one place, and overwhelmed with immediate destruction, a vast multitude of the inhabitants of the globe. These remains are found in greatest abundance in the islands of Cherso and Osero ; end always in what the Abbé FORTIS calls an _ocreo-stalactitic earth_. The bones are often in the state of mere splinters, the broken and confused relics of various animals, concreted with fragments of marble and lime, in clefts and chasms of the strata.[211] Sometimes human bones are said to be found in these confused masses. [Footnote 211: Travels into Dalmatia, p. 449.] 406. A very remarkable collection of bones in this state is found in the caves of Bayreuth in Franconia. Many of these belong, as is inferred with great certainty from the structure of their teeth, to a carnivorous animal of vast size, and having very little affinity to any of those that are now known. The bones are found in different states, some being without any stalactitical concretion, and having the calcareous earth still united to the phosphoric acid, so that they belong to the third, rather than the second, of the preceding divisions. In others, the phosphoric acid has wholly disappeared, and given place to the carbonic. The number of these bones, accumulated in the same place, is matter of astonishment, when it is considered, that the animals to which they belonged were carnivorous, so that more than two can never have lived in the same cavern at the same time. The caves of Bayreuth seem to have been the den and the tomb of a whole dynasty of unknown monsters, that issued from this central spot to devour the feebler inhabitants of the woods, during a long succession of ages, before man had subdued the earth, and freed it from all domination but his own. 407. The fossil bones of the second and third class, but chiefly of the third, have now afforded matter of conjecture and discussion for more than a century. The facts with respect to them are very numerous and interesting, but can be considered here only very generally. The remains of this kind, consist of the bones only of large animals, so that they have generally been compared with those of the elephant, the rhinoceros, the hippopotamus, or other animals of great size The bones of smaller animals have also been found, but much more rarely than the other. It is usually remarked, that the bones thus discovered in the earth are larger than those of the similar living animals.