CAMERON : SUBSIDENCFS OVER PERMIAN BOUNDARY. 351 
the Subsidences on Blackheath. The results of the Exploration 
are greatly in favour of these Subsidences being' due to artificial, 
rather than natural causes, an opinion borne out by Professor 
Prestwich, and expressed also by Mr. Whitaker, of the Geological 
Survey, at the Meeting of the British Association, in York, 1881. 
A PRELIMINARY ACCOUNT OF THE WORKING OF DOWKERBOTTOM 
CAVE, IN CRAVEN, DURING AUGUST AND SEPTEMBER, 1881. 
BY EDWARD B. POULTON, M.A., F.G.S., OF JESUS AND KEBLE 
COLLEGES, OXFORD. 
At a meeting of this Society, held at Sheffield, on December 
14th, 1859, Mr Henry Denny gave an account of the working 
of Dowkerbottom Cave. The exploration had been conducted at 
different times by Mr. Jackson of Settle, Mr. Farrer, and Mr. 
Denny himself. At a subsequent meeting, also at Sheffield, on 
March 9th, 1865, a paper on the same subject was contributed by 
Mr. J. Farrer and Mr. Denny. Since this last paper was read, 
sixteen years ago, till the past summer, the cave has been left 
entirely alone ; and in renewing this long neglected search 
I have been especially helped in having before me an account of 
former work in the " Proceedings " of this Society. The work 
that has been done this summer, with the advantage of so many 
examples of scientific cave-working, tends to confirm some conclu- 
sions formerly arrived at, while others require modification. It 
was therefore in every way right that I should accept the kind 
invitation of your Secretary to read a paper on these later re- 
searches. 
It is first necessary to describe the condition of the cave ; 
and in doing so I will quote from a paper read at York, to the 
Geological Section of the British Association, and written by me 
while the work was in progress. This account, although read, 
has not been published. 
