From these facts it would appear probable that the Cave at Kirkdale was, “during a long succession of years, inhabited as a den by Hyænas, and that they dragged into its recesses the other animal bodies, whose remains are found mixed indiscriminately with their own.”[103] This conjecture is made almost certain by the discovery made by Dr. Buckland of many coprolites of animals that had fed on bones, as well as traces of the frequent passage of these animals to or from the entrance of the cavern or den. A modern naturalist visiting the Cavern of Adelsberg, in Carniola, traversed a series of chambers extending over three leagues in the same direction, and was only stopped in his subterranean discoveries by coming to a lake which occupied its entire breadth. [103] “Reliquiæ Diluvianæ,” by the Rev. W. Buckland, 1823, p. 19. The interior walls of the bone-caves are, in general, rounded off, and furrowed, presenting many traces of the erosive action of water, characteristics which frequently escape observation because the walls are covered with the calcareous deposit called _stalactite_ or _stalagmite_--that is, with carbonate of lime, resulting from the deposition left by infiltrating water, through the overlying limestone, into the interior of the cavern. The formation of the stalactite, with which many of the bones were incrusted in the Cave of Gailenreuth, is thus described by Liebig. The limestone over the cavern is covered with a rich soil, in which the vegetable matter is continually decaying. This mould, or humus, being acted on by moisture and air, evolves carbonic acid, which is dissolved by rain. The rain-water thus impregnated, permeating the porous limestone, dissolves a portion of it, and afterwards, when the excess of carbonic acid evaporates in the caverns, parts with the calcareous matter, and forms _stalactite_--the stalactites being the pendent masses of carbonate of lime, which hang in picturesque forms either in continuous sheets, giving the cave and its sides the appearance of being hung with drapery, or like icicles suspended from the roof of the cave, through which the water percolates; while those formed on the surface of the floor form _stalagmite_. These calcareous products ornament the walls of these gloomy caverns in a most brilliant and picturesque manner.