TRANSACTIONS OF THE SECTIONS. Ill 



position, combining' with the remaining constituents of the dolomite, had formed 

 bicarbonates, readily removeable by the agency of percolating water. In this way, 

 it is possible not merely to account for the formation of the caverns, and a means 

 of access to them, but at the same time to discover what are the causes still in 

 operation which give rise to the production of stalactite, and occasion the irre- 

 gular dolomization of the limestone, — it being evident that the percolating waters 

 charged with bicarbonates of lime, magnesia, &c, may, by a loss of carbonic acid, 

 deposit insoluble carbonate of lime in the form of stalactite, and becoming by this 

 means richer hi bicarbonate of magnesia, act chemically on the neighbouring lime- 

 stone, converting it into dolomite. 



" To test the correctness of these views, a very carefid examination of the clay 

 below the bones was instituted ; it was extremely tenacious, and of a dark reddish 

 brown colour ; patches of red clay were visible in some places ; and in other parts 

 of the mass distinct yellow and black layers were apparent, and nodides, or, more 

 strictly speaking, irregular masses of impure ochrey red iron ore, together with 

 black rounded fragments, evidently arising from the decomposition of a dolomite 

 similar to that before alluded to ; for in the larger fragments this rock was di- 

 stinctly visible on fracture ; and in one or two instances, in which the masses were 

 larger than usual, a brown zone was observable between the black external coating, 

 and the central nearly unaltered dolomite ; large and small masses of the common 

 limestone rock of the quarry were also found in the clay, their surface being honey- 

 combed as if by exposure to the long-continued action of carbonated waters. These 

 phenomena may justly be explained on the supposition that the irregular masses 

 of ochrey iron ore had been derived from the decomposed slaty seams, confirmatory 

 appearances being not unfrequent in other limestone beds connected with the same 

 series of rocks, the slate in these alternating with the limestone on a large scale, 

 and containing irregular nodides of impure iron ore — a red oxide of iron being fre- 

 quently visible at the points of junction. The varied colour of the clay may also 

 be accounted for by the gradual admixture with it of the red oxide of iron from the 

 slaty seams, and the black oxide of manganese accompanied by yellow hydrated 

 peroxide of iron from the dolomitic rock, which may be concluded to have formed 

 a part only of the walls of the cavern, — the honeycombed limestone fragments 

 resulting from the displacement of other portions of previously-fissured limestone 

 rock through the agency of aqueous carbonic acid. The most careful examination 

 presented no facts that at all appeared of an opposing character ; the clay was 

 diligently searched, and some of its laminated portions, having a sandy appear- 

 ance, were examined by the microscope for the siliceous coverings of infusoria, 

 minute rounded grains of sand, and any other matter that might suggest the wash- 

 ing in of the contents of the cavern through free communication of its opening 

 with external waters ; nothing was, however, discovered but very minute frag- 

 ments of slate, still further confirmatory of the position before advanced." 



The author assigns reasons for adopting the opinion that the bones were intro- 

 duced to Oreston Cave by animal agency, and not by accidental falling into fissures. 



He enumerates the principal remains found in the cavern, viz. of the thick- 

 skinned quadrupeds at least four genera, — Elephant, Rhinoceros, Horse, Ass or 

 Zebra, and Hog. Of Camivora, Bears of two species, Felts, Wolf, and a small 

 rodent. 



The ruminants probably included one or two species of elk or deer, and two or 

 three animals allied to the ox. Teeth of the sheep or goat were also brought from 

 the clay, but there is reason to be doubtful about the genuineness of many of the 

 last-named specimens. 



Among the remains of animals of the deer-tribe, is especially mentioned an in- 

 teresting fragment of jaw, containing several teeth, developed by me with some 

 pains from a large and nearly solid mass of stalagmitic matter, containing various 

 other imbedded bones. There occurred too a very few fractured specimens of teeth 

 suggestive of those of a giraffe (this possibility having been ascertained by com- 

 parison with figures of fossil teeth contained in a paper by Dr. Falconer and Capt. 

 Cautley, in the ' Proceedings of the Geological Society of London '), and a small 

 horn core may, it is presumed, also indicate the presence of an animal allied to a 

 species of this interesting quadruped *. 



* Two premolars of a Camel. 



