The dread of the supernatural, which preserved the European caves from disturbance, was destroyed in the sixteenth and seventeenth centuries by the search after “ebur fossile,” or unicorn’s horn, which ranked high in the materia medica of those days as a specific for many diseases, and which was obtained, in great abundance, in the caverns of the Hartz, and in those of Hungary and Franconia. As the true nature of the drug gradually revealed itself, the German caves became famous for the remains of the lions, hyænas, fossil elephants, and other strange animals, which had been used for medicine.[89] Footnote 89: _Cave Hunting_, p. 11. These caves were investigated mainly by geologists or palæontologists, searching for evidence as to the extinct animals that formerly occupied them. Indications of the presence of man were unsuspected, and, if found, disregarded. Thus much of the evidence of man’s early history was doubtless unwittingly destroyed. The Franconian caves were explored towards the end of the eighteenth century, and described by Esper (1774), Rosenmüller (1804), and Dr. Goldfuss (1810). The most famous of these was the cave of Gailenreuth. Here, for the first time, investigations were carried out systematically, the finds classified, and, since they indicated the co-existence of man and extinct mammals, theories as to their significance and derivation filled the air. In 1861 William Buckland (1784-1856), Professor of Mineralogy at Oxford (afterwards Dean of Westminster), visited the caves, and kindled that interest in cave-exploration which was to produce such remarkable results in England. [Sidenote: =Oreston.=] In the same year the first bone-cave systematically explored in the country was discovered at Oreston, near Plymouth, and the deposits proved the former existence of the rhinoceros in that region. [Sidenote: =Kirkdale.=] More famous was the exploration of the Kirkdale Cave, near Helmsley, in Yorkshire, discovered in 1821, in a limestone quarry, and investigated and described by Dr. Buckland.[90] He found remains of the broken and gnawed bones of the rhinoceros, mammoth, stag, bison, etc., which had been the prey of the hyænas inhabiting the cave, and he traced their origin to a universal deluge. Subsequently he examined the remains from other caves, and summarised his conclusions in _Reliquiæ Diluvianæ_, published in 1824. Dr. Buckland was henceforward the acknowledged authority on bone caves and their contents, and to his disbelief in the contemporaneous existence of man with the cave animals may be traced much of the incredulity with which all evidence of early man in Britain was received for more than a generation. Footnote 90: _Phil. Trans. Roy. Soc._, 1882.