THE BLACKHEATH SUBSIDENCES. 
237 
the Metropolitan Board of Works, without any attempt at 
exploration. In November, 1880, two other holes suddenly 
appeared, and the deeper of these two holes is that the 
examination of which has just been concluded. The Metro- 
politan Board having stated, in answer to the Astronomer 
Royals request that they should explore the first hole, that 
they had no funds for that purpose, the matter was taken up 
by the Lewisham and Blackheath Scientific Association, the 
then President, Mr. J. K. Laughton, R.N., and Mr. H. W. 
Jackson, F.R.A.S., the Hon. Secretary, being especially zealous 
in the matter. A small sum was voted by the Association for 
the exploration, but was soon exhausted ; and money coming in 
but slowly from the neighbourhood generally, April had 
arrived before the Subsidence committee had received sufficient 
funds to enable them to continue the work. 
The hole which appeared in April, 1878, and that which 
has just been examined, were almost identical in size and 
appearance. The last was, when first seen, like a nearly 
circular shaft with vertical sides, and 18 feet deep.* It was 
in its longer diameter 7 ft. 8 in., and 6ft. 9 in. in the shorter. 
When the fallen earth from the bottom was removed, the sides 
were found to recede till the hole became about 14 feet in 
diameter, at a depth of about 22 feet. The third hole, that 
near Eliot Place, was shallower than either of the other two, 
and somewhat different in shape. The difference, however, 
was chiefly one of proportion, the shaft-like portion of the 
hole being very short, and its sides receding more rapidly than 
in the other two. The Eliot Place hole, after remaining open 
some months, was filled up by the Metropolitan Board of 
Works towards the end of April. 
During the first brief exploration of the hole, the heap of 
material at the bottom was carefully examined by Mr. Jackson 
during its removal, and found by him to correspond exactly to 
the sand and clay which formed the sides of the hole at and for 
7 feet below the surface. On recommencing the work in April, 
the first shaft, 11 ft. 3 in. by 9 ft., which had been carried to 
a depth of 16 feet, was considered unnecessarily large, and 
consequently expensive ; and the work was carried on below 
that depth by means of a shaft 6 ft. by 5 ft. 6 in. Below 
the surface-material were foimd Blackheath pebble beds of 
the ordinary type and orange colour. At a depth of 34 feet 
water appeared, and continued to fill the hole to about that 
level during the progress of the excavation, so that a pump 
became necessary. From 36 to 42 feet, whitish sand and 
pebbles were brought up. The proportions of sand to pebbles 
varied considerably, and occasionally differed in a marked 
* See Engineer, Feb. 4, 1881. 
