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the neighbourhoods of Charlton and Lewisham, though else- 
where, for the most part, hidden from sight bj 7- the agency of 
faults or surface deposits. Above the Chalk, along this 
escarpment, lies the Thanet Sand; then come the Woolwich 
beds ; and, lastly, the Oldhaven or Blackheath pebble beds 
crown the plateau. Further inland, at and around Shooter’s 
Hill, the London Clay exists in considerable thickness, and 
extends westward between Kidbrook and Eltham in a slight 
synclinal fold. At Eltham, the surface is again composed of 
the Woolwich and Blackheath beds. The newest beds in the 
district immediately around Blackheath are the gravel capping 
Shooter’s Hill, which is said by Mr. Whitaker * to be inter- 
mediate in age between the Lower Bagshot beds and the 
Boulder Clay, and the gravel and alluvium of the Thames 
Valley. 
A glance at the Geological Survey map, shows that the 
Blackheath pebble beds and the Woolwich beds crop out on 
the northern, western, and southern sides of Blackheath. To 
these may perhaps be added the Thanet Sand, which, though 
it is shown on the map only on the north and west, and just 
round the south-west corner, was seen here and there by 
Mr. Prestwichf at the bottom of the cutting between Black- 
heath station and tunnel ; and I was informed by Mr. Chapman, 
station-master at Blackheath, that the station there is founded 
on what can only be Thanet Sand. The dip of the various beds 
at Blackheath is very slight in amount, and is southerly in 
direction. In Westcombe Park (east of Greenwich Park) and 
the adjacent railway cutting, they are very well shown at 
heights only 15 to 20 feet above their level in the cutting 
west of Blackheath station, though the distance, measured 
along a line ranging due north and south, is about a mile and 
a furlong. It will be seen, therefore, that the geological 
evidence at Blackheath is much greater in amount than usual, 
and that it tends to show that the beds are lying nearly level, 
and are free from faults or disturbances of any appreciable 
magnitude. 
There is evidence, in the appearance of certain spots on 
Blackheath, that holes like that to be described have disclosed 
themselves from time to time, and been filled up without any 
curiosity having been (apparently) excited as to their origin. 
But in April, 1878, the sudden appearance of a cylindrical 
hole, about 20 feet deep and from 7 to 8 feet in diameter, made 
more impression on the minds of the inhabitants of the 
neighbourhood than had previously been the case. The hole 
was, however, after remaining open a few weeks, filled up by 
* Whitaker, Guide to Geology of London, p. 56 (3rd edit.). 
t Quart. Journ. Geol. Soc. vol. x. p. 104. 
