106 
JOURNAL OF THE PLYMOUTH INSTITUTION. 
1859 are described by Mr. Pengelly as associated with a mass of 
heterogenous materials, consisting of limestone debris, sand, and 
"tough, dark, unctuous clay," partially cemented by stalactite, and 
" in the cemented and uncemented portions of the bed.* 
Mr. H. C. Hodge, writing of the discoveries of the same date, 
implies that the bones were generally found on or in a soft, dark-red, 
tenacious clay.t The bones in the Pomphlett cave of 1878 were 
invested by a dark-red, tough, greasy clay, which where the bones 
were thickest at once — as already noted — suggested the value of 
the hypothesis of Sir H. De la Beche, that some clay observed at 
Oreston by him was " apparently impregnated with animal matter. "J 
The bones found at Cattedown were in clay ; on the Hoe they have 
been associated with sand and gravel. Those found on the raised 
beach are of course out of our present purview. 
But there are other points to be noted in these fissure deposits 
beyond this variation in character. Dr. Buckland says, that in one 
cavern at Oreston, " where the quantity of diluvium was very 
great, it was stratified, or rather sorted and divided into laminae of 
sand, earth, and clay, varying in fineness, but all referable to the 
diluvial washings of the adjacent country. It is often partially 
interspersed with small fragments of clay-slate, and quartz." § I 
have elsewhere noted associated phenomena in connection with the 
alluvial deposits on the Hoe. At Deadman's Bay there are the 
remains of a huge pocket deposit of similar character, chiefly con- 
sisting of white clay. At Long Room I have recently found quartz 
pebbles in the earthy filling of small fissures in the limestone 
there. At Yealm Bridge there are caverns containing waterworn 
debris identical in character with the materials of the river bed 
many feet below. Similar appearances have presented themselves 
in connection with the fissures at Billacombe. 
Since I first directed attention to the Hoe deposits, they, with 
others at Deadman's Bay and Mount Batten, have been examined 
by Mr. J. H. Collins, who found therein pebbles of quartz, lime- 
stone, schorl rock, greenstone, grit, clay-slate, tourmaline schist, 
granite, elvan, flint, chert, all of which he considered had been 
* Op. cit. Cited "Devon Assoc. Trans ," vol. v. part i. p. 298. 
f Op. cit. Cited "Devon. Assoc. Trans.," vol. v. part i. p. 303. 
% "Rep. Geo. Cornwall, Devon, and West Somerset," p. 413. Cited 
"Devon. Assoc. Trans.," vol. v. part i. p. 285. 
§ Op. cit. pp. 82, 83. Cited "Devon. Assoc. Trans.," vol. v. part i. p. 261. 
