The Cave of Uphill,[194] discovered in 1826, by some workmen, and explored by the Rev. D. Williams, merits especial notice, from the peculiar conditions under which the remains of the extinct animals occurred. Like the other caves of the Mendips, it consists of fissures opening into chambers. In the upper part of one of these fissures were the remains of rhinoceros, hyæna, bear, horse, bison, and wild boar, imbedded in loam which rested on two large masses of limestone that had fallen so as to block up the fissure. Below this were no remains of the extinct animals, and the fissure ultimately led into a cave opening upon the line of cliffs. This latter had been inhabited within historic times, since many bones of sheep, or goat, and pieces of pottery, were met with, as well as a coin of the Emperor Julian. In this case, owing to the extraordinary accident of the fissure being blocked up by a fall of stone, the pleistocene accumulation is vertically above the historic; and had the barrier given way, Mr. Williams would undoubtedly have discovered the remains of the extinct mammalia, lying in a heap above the comparatively modern historic stratum. It seems to me very probable that some such accident may have caused the occurrence of the pleiocene machairodus in the Kent’s Hole cavern, in association with the pleistocene mammalia. In the long lapse of ages between the pleistocene and the present day, such accidents would be likely to occur in some few caverns, and we might expect to find remains of widely different ages, in certain exceptional cases, lying side by side, or even the older resting vertically over the newer. At all events we must conclude, that superposition, or association, cannot be rigidly enforced as tests of relative age in all ossiferous caverns. _The Hyæna-den of Wookey Hole._ The Hyæna-den of Wookey Hole,[195] near Wells, on the south side of the Mendips, which I explored with the Rev. J. Williamson in 1859, and in the following years with Messrs. Willett, Parker, and Ayshford Sanford, is worthy of a more detailed notice, because it was among the first caverns in this country in which works of art were found under conditions that proved the co-existence of man with the extinct mammalia.