TRANSACTIONS OF THE SECTIONS. 123 



from Stalagmite) and was in no part cemented. No traces of fossils were ionnd 

 in it. The next 32 feet in depth were occupied with materials similar to thoso just 

 mentioned (the sand being somewhat more abundant), with the addition of a 

 tough, dark, unctuous clay. Between this mass of heterogeneous materials and 

 the western, or what may be called the river-wall of the cavern, occurred a nearly 

 vertical brecciated plate or dyke, which the workmen denominated " Callis ;" ex- 

 tremely tough, and quite as difficult to Avork as the compact limestone itself. It 

 may be described as an approximately vertical plate of stalactitic carbonate of 

 lime, containing, at by no means very wide intervals, masses of breccia, made up 

 of the materials just named as composing the accumulation in contact with and 

 on its eastern or hill side, and cemented together by carbonate of lime. Some of 

 these masses measured fully a yard cube, but the general thickness of the Callis 

 was about 2 feet. This was the bone-bed, that is to say the bones were found 

 alike in the Callis and in the mass of heterogeneous materials beside it, in the 

 cemented and uncemented portions of the bed. They were foimd alike at all 

 heights or levels, in the lumps of breccia, in the pure stalagmite between them, 

 and in the looser and less coherent portion of the accumulation ; thereby suggest- 

 ing that the cavern was slowly and gradually filled with limestone debris detached 

 from the rock in which the cavern occurred, with sand transported, at least, some 

 distance, and with mud; not each in definitely successive periods, but together; 

 with occasional pauses or periods of cessation ; the proof of such pauses being the 

 frequent presence of the portions of pure stalagmite separating series of brecciated 

 masses made up of angular limestones, clay, and sand, lying one above another in the 

 same nearly vertical plane. The rapidity of the infilling, and hence the time re- 

 quired for the process, seem of necessity to be measured by the rate of deposition of 

 the stalagmite, whatever that may have been. It appears, too, that throughout the 

 entire period — be it long or short — required for and represented by the accumu- 

 lation of the materials under consideration — alike during the periods of active and 

 of tardy accumulation — bones of various animals were introduced and inhumed, 

 and that there was no marked cessation in this part of the work, since the bones 

 were found as frequently in the pure stalagmite as elsewhere. The bones were 

 frequently in a very fragmentary condition, as if broken by fragments of rock falling 

 on them. 



A somewhat considerable number of clay balls, generally ellipsoidal, and varying 

 from an inch and a half to two and a half in greatest diameter, were found in the 

 clay throughout the bone-bed, but not above or below it. 



Beneath the materials just described, occurs a bed of dark, very tough, unctuous 

 clay, known to be 12 feet thick, but perhaps more, as its base has not been reached. 



The workmen positively assert that the roof of the cavern, 8 feet in thickness, 

 was of sound unbroken limestone, and that the stones and other materials could not 

 have fallen in from above ; but unfortunately they with equal positiveness affirm that 

 there was no external opening whatever, either vertical, terminal, or lateral ; the 

 author, however, is of opinion that there is ample reason for believing that the 

 cavern originally communicated with the surface by an opening- sufficiently wide 

 to allow the passage of all its contents, and that it was thus filled ; but whether 

 animals fell, or were dragged in, or whether the bones found there were wholly or 

 partially the disjoined remnants of dead animals washed in, he would not under- 

 take to say. 



In conclusion Mr. Pengelly said, " Without the pale of philosophy exists a many- 

 motived curiosity on this subject, quite as powerful, if not so intelligent or manage- 

 able, as that which leads, yet is under the guidance of science. Recent discoveries 

 have made it not a question of exploration now or at some future time ; the alter- 

 natives are prompt systematic investigation, or the abandoning of our caverns to 

 be ransacked by fossil dealers." 



On Slickensid.es. By John Price, M.A. 



This commimication (in the absence of the author read by J. J. Walker, M.A.) 

 included in the term " Slickensides " every mineral surface which, apart from 

 Crystallization, exhibits an extraordinary degree of polish. The author invited 

 the attention of observers to it, and mentioned his having observed it in situ only 



