conspicuous chalk, points to a strong desire for the preservation: 

 of secrecy on the part of the designers of the deneholes. 



The careful removal of the conical heaps of debris at the 

 base of the open shafts disclosed a precisely similar state of 

 things in each case. The heap was found to consist of a low- 

 cone of gravel surmounted by a steeper cone of Thanet Sand.. 

 Of course there was a little sand in the gravel, and a slight 

 admixture of gravel with the sand, but in the main, the sand 

 lay above the gravel. In the gravel, and usually not far above 

 the smooth chalk floor, were considerable numbers of large 

 flints that had been more or less squared. They had evidently 

 been used for steining the uppermost seven or eight feet of the 

 shaft, which is in the surface gravel. The history of the formation, 

 of the heap had, in the opinion of our President, been this : On 

 the pits becoming disused and neglected, the steining flints had 

 fallen down the shaft, accompanied by more or less of the gravel. 

 The gravel had then been worn back by the action of rain and' 

 frost till a broad funnel-shaped opening was produced, on the 

 sides of which grass subsequently grew, and thereby checked 

 the denudation. The Thanet Sand forming the upper part of" 

 the mound appeared to have been the slow and gradual deposit 

 of centuries, the weathering of the sand part of the shaft having 

 been very even and regular. Here and there were found lumps 

 of chalk, which had evidently fallen down from the immediate 

 neighbourhood of the shaft. Bones of various animals — those- 

 of the ox, horse, and dog predominating — were found here and 

 there in the mounds, and in one of the pits the femur and some 

 other bones of a man were discovered ; the skull, however, was. 

 wanting. 



In tunnelling from the open deneholes into adjacent closed 

 ones, passages were directed towards the shaft of the pit it was 

 desired to enter. Experience showed that the denehole excavators- 

 had no scientific means of ascertaining the direction towards- 

 which they were working, but that they trusted to prevent 

 intercommunication partly by the preservation of a certain (though 

 in itself insufficient) distance between the several shafts, and partly 

 by a keen perception of the relation between the intensity of 



