These caves and fissures were at all levels in the cliff, and in some the bottoms were covered with a stratum of marine sand with sea shells, which showed that they had been washed by the sea before they had been filled by the ossiferous débris. Most of them had probably been filled by streams in the same manner as Gailenreuth and Wirksworth. They abound on the coast merely because a clear section has been worn by the waves. A straight cut through the rocks in any part of the district would probably show them to occur in equal abundance inland. _Caves in Pembrokeshire._ The patches of limestone on the opposite side of Caermarthen Bay, in the neighbourhood of Tenby, also contain ossiferous caverns. The Rev. G. N. Smith,[188] of Gumfriston, has made a fine collection of bones and teeth of mammoth and hyæna, from a fissure in the Blackrock Quarry, close to Tenby, from a fissure in the cliff on Caldy Island, and from the Coygan cave in an outlier of limestone, near Pendine, and has discovered flakes of flint and of a peculiar hornstone in the “tunnel cave” termed the Hoyle, underneath stalagmite, in a stratum containing bones of the bear and reindeer. With the exception of the fissure in the Blackrock Quarry none of these have been fully explored. On a visit to Tenby, in 1872, I obtained many flint flakes, and bones broken by man, from the breccia in the Hoyle; and from a fissure on Caldy Island, numerous bones and teeth of young wolves, which represented a whole litter, and two metatarsals of bison, cemented together into a compact mass. The discovery of mammoth, rhinoceros, horse, Irish elk, bison, wolf, lion, and bear, on so small an island as Caldy, indicates that a considerable change has taken place in the relation of the land to the sea in that district since those animals were alive. It would have been impossible for so many and so large animals to have obtained food on so small an island. It may therefore be reasonably concluded that, when they perished in the fissures, Caldy was not an island, but a precipitous hill, overlooking the broad valley now covered by the waters of the Bristol Channel, but then affording abundant pasture. The same inference may also be drawn from the vast numbers of animals found in the Gower caves, which could not have been supported by the scant herbage of the limestone hills of that district. We must, therefore, picture to ourselves a fertile plain occupying the whole of the Bristol Channel, and supporting herds of reindeer, horses, and bisons, many elephants and rhinoceroses, and now and then being traversed by a stray hippopotamus, which would afford abundant prey to the lions, bears, and hyænas inhabiting all the accessible caves, as well as to their great enemy and destroyer man. We shall see in the ninth chapter that the elevation of the whole district above its present level is part of the general elevation of north-western Europe, and no mere small or local phenomenon. _Cave in Monmouthshire._