442 



THE GEOLOGIST. 



Between tliis mass of lieterogeuous materials and the western- or wliat may 

 be called the river-wall of the cavern there occnrred a nearly vertical brecciated 

 plate, or dyke, wliich the workmen denominated " callis," extremely tough, and 

 quite as difficult to work as the compact limestone itself. The only means of 

 severing it was by blasting ; and being considerably less compact than tlie 

 limestone, the expansion of the ignited powder told on it with much less 

 effect. It may be described as an approximately vertical plate of stalactitic car- 

 bonate 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 oi- hill-side, and cemented together by car- 

 bonate of lime. Some of these masses measured fully a yard cube, but the 

 general thickness of the " caUis" was about two feet. This was tlie bone- 

 bed, that is to say, the bones were found alike in the " callis," and in the 

 mass of heterogenous materials beside it, in the cemented and uncemented 



f)ortions of the bed. They Avere found alike at aU heights or levels, in the 

 umps of breccia, in the pure stalagmite between them, and in the looser and 

 less coherent portion of the accumulation, thereby suggesting that the cavern 

 was slowly and gradually fiUed with limestone-debris detached from the rock 

 in which the cavern occurs, with sand transported at least from 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 limestone, clay, and sand, lying one 

 above another in the same nearly vertical plane. The rapidity of the inlilling, 

 and hence the time required for the process, seem of necessity to be measui-ed 

 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 accumulation of the materials now under considera- 

 tion — 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. In that portion of the series which is destined for 

 the University Museum, at Oxford, a mass of this stalagmite will be found 

 containing a fine jaw wdth teeth, beautifully white and entirely free from any 

 trace of soil. The bones are frequently in a very fragmentary condition, many 

 of them being mere splmters, as if broken by fragments of rock falling on them ; 

 this, however, may be partly due to the rough handling of the w^orkmen in ex- 

 tracting them. 



" I always know," said the old quan-yman before alluded to, " when we are 

 coming to bones where there's clay, for the clay is always fat-like. I suppose 

 'tis the fat of the beasts that the bones belonged to." Evidently he was not 

 enough of a philosopher to explain phenomena by calling to his aid the 

 " plastic," or the " sportive powers of Nature ;" and probably he was so be- 

 nighted as never to have heard of the discovery of " proclu-onism." 



A somewhat considerable number of clay-baUs, generally ellipsoidal, and 

 v arying from an inch and a-half to two and a-half inches in greatest diameter, 

 were found in tlie clay throughout the bone-bed, but not above nor below it. 



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

 tough, unctuous clay ; known to be twelve feet thick, but perhaps more, as 

 it s l)ase has not been reached. It seems to be of the same character as that 

 mentioned by Mr. Wliidbey in his description of the third cavern, already quoted. 

 ()ceasionally it contains a few very small angidar stones, but with this excep- 

 tion it is ported ly liomogenous. No traces of fossils have been found in it. 

 ^ it now remains to consider how the contents of the cavern were introduced. 

 The Nvorkmen most positively assert that it never was an open fissure ; that the 



