It was in the course of the year 1821, that some labourers working at a quarry, discovered by chance the opening, which was closed by rubbish, covered over with earth and turf. It is about 100 feet above the neighbouring brook. It can be entered to the distance of 150 or 200 feet, but we can only walk erect in some places, on account of the stalactites. On its sides there are seen spines of sea-urchins and other marine remains, incrusted in the mass of the rock; but it is on the bottom, and there only, that there is found the stratum of mud, of about a foot thick, stuck full of bones, as at Gaylenreuth. This mud, and the bones which it contains, are, in various places, covered or penetrated with stalactite, especially near places where the rock has lateral fissures.
The discovery having acquired much celebrity, a great number of people procured bones from it, and placed them in various public depots. Specimens have been deposited in the York Institution, that of Whitby and Bristol, the British Museum, the Museum of Oxford and Cambridge, and by Mr Young of Whitby, in the College Museum of Edinburgh; but the finest collection of the bones of Kirkdale was presented to Cuvier, and by him deposited in the Royal Cabinet in Paris. The greatest number of these bones without comparison, belong to hyenas of the same species as those of the caverns of Germany; but there are also many of other large and small animals, which Mr Buckland supposes to form twenty-one species. From the pieces which I have under my eye, says Cuvier, there indisputably occur bones of the elephant, hippopotamus, horse, an ox of the size of the common deer, rabbits, field-rats; also bones of some other carnivora, namely, of the tiger, wolf, fox, and weasel. All these bones and teeth are accumulated on the ground, broken and gnawed, and there are even seen marks of the teeth which have fractured them. There are even intermixed with them excrements which have been recognized as perfectly similar to those of the hyena[436].
The hills in which these caverns occur resemble each other in their composition: they are all of limestone, and all produce abundance of stalactites. These stalactites line the walls, narrow the passages, and assume a thousand various forms. The bones are nearly in the same state in all these caverns: detached, scattered, partly broken, but never rolled, and consequently not brought from a distance by water; a little lighter and less solid than recent bones, but still in their true animal nature, very little decomposed, containing much gelatine, and not at all petrified. A hardened, but still easily frangible or pulverisable earth, also containing animal parts, and sometimes blackish, forms their natural envelope. It is often impregnated and covered with a crust of stalactite. A covering of the same nature invests the bones in various places, penetrates their natural cavities, and sometimes attaches them to the walls of the cavern. This stalactite is often coloured reddish by the animal earth which is mixed with it. At other times its surface is stained black; but it is easy to see that these appearances are caused by modern occurrences, and have no immediate connection with the cause which brought the bones into these cavities. We even daily see the stalactite increasing and enveloping here and there groups of bones which it had formerly respected.
This mass of earth, penetrated by animal matter, indiscriminately envelopes the bones of all the species; and, if we except some found at the surface of the ground, and which had been transported there at much later periods, which may also be distinguished by their being much less decomposed, they must all have been interred in the same manner, and by the same causes. In this mass of earth there are found, confusedly mingled with the bones (at least in the cave of Gaylenreuth), pieces of a bluish marble, of which all the corners are rounded and blunted, and which appear to have been rolled. They singularly resemble those which form part of the osseous brecciæ of Gibraltar and Dalmatia.
Lastly, what further conspires to render this phenomenon very striking, is, that the most remarkable of these bones are the same in these caverns, over an extent of more than two hundred leagues. Three-fourths and upwards belong to species of bears, which are now extinct. A half, or two-thirds of the remaining fourth, belong to a species of hyena, which is equally unknown at the present day. A smaller number belong to a species of the tiger or lion kind, and to another of the wolf or dog genus; lastly, the most diminutive have belonged to various small carnivora, as the fox, the polecat, or at least species very nearly allied to them, &c.
The Kirkdale Cavern, however, forms a notable exception, inasmuch as none, or very few, bones of bears are found in it, and in its being the hyena that appears to predominate among the carnivora.
The species so common in the alluvial formations, the elephants, rhinoceroses, horses, oxen or aurochs, and tapirs, are of very rare occurrence in the caves of Germany. There are even some in which no one is said to have found them, and the only bones of herbivora mentioned are remains of deer. In this point also, however, the Kirkdale cave differs much from the others, inasmuch as it abounds almost as much in bones of large and small herbivora, as in bones of carnivora. All the great pachydermata of the alluvial formations are seen in it: the elephants, rhinoceroses and hippopotami. There are also seen in it bones of oxen, deer, and even small bones of mice and birds. But there are no bones of marine animals of any species, either at Kirkdale or in Germany. Those who have pretended that they saw bones of seals, morses, or other similar species, have been led into error by the hypothesis which they had previously adopted.
These bones of carnivora, so numerous in the caves, are rare in the great alluvial strata; the hyena alone has been seen in any quantity at Canstadt, near Aichstedt, and in some other places. There have also been found some traces of bears in Tuscany and Austria, but their relative proportion is always infinitely less than in the caves; and it is always sufficiently proved by these circumstances, that these various animals have lived together in the same countries, and have belonged to the same epoch.
Cuvier concludes, there can only be imagined three general causes which might have placed these bones in such quantity in these vast subterranean cavities. Either they are the remains of animals which inhabited these abodes, and which died peaceably there; or inundations and other violent causes have carried them into these cavities; or, lastly, they had been enveloped in rocky strata, the dissolution of which produced these caverns, and they have not been dissolved by the agent which carried off the matter of the strata.