The remains of the Drift fauna are usually found mixed up and washed together in caves and rock-crevices. From the investigation of the caves in Thuringia, Franconia, and elsewhere practically proceeded the first knowledge of the Drift fauna of Central Europe. Here, right among the bones of primeval animals, were also found bones and skulls of man. The strata in which they were discovered appeared undisturbed; that they came into the old burial-places of the Drift fauna subsequently--perhaps by an intentional burial of relatively recent times--was thought to be out of the question. The discovery that became most famous was Esper’s, in one of the richest caves of “Franconian Switzerland,” the Gaillenreuth cave. There, in 1774, Esper found a man’s lower jaw and shoulder-blade at a perfectly untouched spot protected by a stone projection in the cave wall, in the same loam as bones of the cave-bear and other Drift animals. Later, a human skull with some rude potsherds of clay came to light in another place. Esper argued thus: As the human bones (lower jaw and shoulder-blade) lay among the skeletons of animals, of which the Gaillenreuth caves are full, and as they were found in what is in all probability the original stratum, I presume, and I think not without sufficient reason, that these human limbs are of equal age with the other animal fossils. The Cuvier catastrophe theory could not allow this inference; according to that theory it was a “scientific postulate” that man could not have appeared on the earth until the alluvial period, and therefore after the Drift fauna had become extinct. Therefore, in spite of appearances, the human bones must have been more recent; and it was indeed absolutely proved that the skull that Esper had found in the cave with the rude clay potsherds originated from a burial in the floor of the cave. As this was full of remains of Drift animals, the corpse, which had been covered with the earth that had been thrown up in digging the grave, was necessarily surrounded by these remains, and even appeared embedded in them. [Sidenote: The Story of the Caves]