Royal Society of Edinburgh, 33 1 



Gumming of Denbigh, were visited by the author in the autumn of 

 1837. The principal cave is a fissure in a grand mural escarpment 

 of the mountain limestone of Wales, about two miles and a half south- 

 west of St. Asaph, and occurs half way down the precipice, which 

 seems to be about 250 feet in height. It forms at that point the 

 southern boundary of the limestone, which constitutes the basis of 

 the Vale of Clwyd ; and is divided from the extensive greywacke 

 slate formation of that county by the narrow picturesque vale of 

 Cyffredin, through which the river Elwy flows. 



The hill of Cefn consists of parallel beds of limestone, which the 

 extensive quarries on its southern flank show to have a regular dip 

 of about 8°. This cave was discovered in 1830 to contain earthy 

 deposits exceedingly rich in bones of mammifera : and, since that 

 period, they have been much employed as a manure by Mr. Lloyd, 

 the proprietor. During the excavations for this purpose, many teeth 

 and fragments of larger bones, so entire as to be readily recognised, 

 have been obtained. An interesting collection of them is preserved 

 at Cefn House, and some are in the hands of the author. Among 

 the former, he noticed part of the humerus and a molar tooth of a 

 rhinoceros, several teeth and bones of the hyaena, and beautiful teeth, 

 and a considerable portion of the lower jaw, of a bear. Dr. Traill 

 has in his possession two phalanges and two teeth of a bear ; a pha- 

 lanx of a large Fells, resembling the tiger ; parts of the tibia, and of 

 the astragalus, and a phalanx of a large Bos ; portions of the meta- 

 carpus of an immense ruminant, apparently a deer ; besides a variety 

 of fragments, not so easily ascertained on account of their mutilated 

 state. 



The materials which filled up the fissure or principal cave almost 

 to its roof, are regularly stratified. They formed together a mass of 

 earthy matter twelve feet in thickness. The first or upper bed con- 

 sists of layers of clay and very fine sand, two feet thick. The second 

 bed is of plastic clay-marl, containing many small water- worn pebbles, 

 chiefly of clay-slate, two feet thick. The third is a stratum so filled 

 with broken and comminuted bones, as apparently to consist entirely 

 of that material, two feet thick. It is in this bed that all the bones 

 mentioned, except those of the bears, are found. Immediately below 

 is the fourth bed, consisting of plastic marl-clay, with many water- 

 worn pebbles of slate and compact felspar, with angular pieces of 

 limestone ; this is also two feet thick. The fifth bed consists of fine 

 sand, which seldom contains any pebbles. It rests on the floor of 

 the cavern, and has usually a depth of four feet. In one part of the 

 cave, however, Dr. Cumming detected below this bed a floor of hard 

 stalagmite, about sixteen feet square ; and on breaking it up, bones 



