302 
RAYGILL FISSURE. 
The uppermost stratum is composed of fine unctuous laminae 
of bluish clay, which turns a brown colour with exposure to the 
atmosphere ; between each lamina of clay there is a minute bed of 
very fine sand, by means of which the clay can be separated into 
very thin layers of considerable size. The middle stratum of sand 
contains numerous boulders of stone, mostly sub-angular in form. 
These, so far as the Committee have had an opportunity of ex- 
amining" them, are composed principally of limestone and grit rock. 
No bones have been found in this bed. The third or lowest 
stratum is a brown sandy clay, containing numerous well-rounded 
water-worn pebbles of limestone and sandstone, apparently derived 
entirely from rocks occuring in the neighbourhood. Intermixed 
with these, especially near the base of the section, are numerous 
bones and teeth. The sands and clays surrounding or forming the 
matrix of the bones are cemented together, forming a hard mass 
enclosing the animal remains. The bones for the most part have 
lost much of their gelatine, and when newly exposed are very soft 
and friable, and being cemented in the hard enveloping matrix it is 
rarely that a bone can be secured which is anything near per- 
fect: they split and break in any direction with the matrix, and 
remain imbedded in it. Both the pebbles, or boulders, and the 
bones, are dark chocolate in colour externally, merging on black. 
The material was removed from the face of the Quarry back- 
wards, and a considerable number of bones were found in the 
lowest stratum exposed. After penetrating for a distance of 15 
feet, the Cave terminated in this direction by a vertical wall of 
limestone, and from this point the fissure descended almost , 
vertically for a distance of about 27 feet. The limestone, which 
formed a wall from 2 to 6 feet thick between this vertical fissure 
and the Quarry, was removed, and the contents of the Cave worked 
down to a level with the lowered front of the limestone : this 
method of working has been pursued to the present time. The 
base of the Cave has been lowered 27 feet, and it extends from 
the face 1 9 feet into the limestone. The vertical fissure is filled 
up for a portion of its depth by bone earth, similar in character 
