T. V. Holmes—Geology of Blackheath and Greenwich. 211 
Fic. 4a. Sladina cateniformis, gen. et sp. noy. Same specimen.  Celluliferous 
TaCe wens 
5. Ditto. Isolated segment. Celluliferous face. x 5. 
5a. Ditto. Same specimen. Reverse face. x 4. 
6. Ditto. Isolated apical segment. Celluliferous face. x 5. 
», 7 Ditto. Reverse face of disjointed specimen. x 4. 
7a. Ditto. Same specimen. Celluliferous face. x 4. 
8. Ditto. Variety or later stage with lateral spines. Reverse face. x 4. 
8a. Ditto. Same specimen. Celluliferous face. x 4. 
,, 9. Ditto. Variety with spined terminal segment. Reverse face. x 4. 
5, 9a. Ditto. Same specimen. Celluliferous face. x 4. 
V.—Recent Grotogicat [NFoRMATION ABOUT BLACKHEATH. 
By T. VY. Houmzs, F.G.S8. 
(WITH A MAP.) 
GLANCE at a geological map shows Blackheath and Greenwich 
re Park at the western end of the Lower Tertiary escarpment 
which is conspicuous on the southern side of the Thames as far 
eastward as Erith. 
This escarpment has the Chalk visible here and there at its base. 
Above the Chalk comes the Thanet Sand, then the Woolwich Beds, 
while the plateau is capped by the Blackheath Beds. Around 
Shooters Hill the London Clay comes on above the Blackheath Beds, 
and is itself capped at Shooters Hill by gravel of later date. At 
Blackheath the surface is composed of the Blackheath Pebble Beds. 
But before mentioning the recent workings there, it is necessary to 
recall events which took place between twenty-five and thirty years 
ago on that well-known Common. 
On Thursday, April 12th, 1878, after a night of very heavy rain, 
it was found that at the spot marked A on the map, south of the 
Shooters Hill Road, and north of that between the south-west corner 
of Greenwich Park and Morden College, a subsidence had occurred. 
This, after some little delay, was filled up by the Metropolitan Board 
of Works. Early in November, 1880, another appeared some distance 
south-west of the first (B), and on November 19th a third, not far 
from the first, marked on the map as C. As regards shape, they all 
agreed in being considerably wider at the bottom than at the top. 
But that at B was shallower, and widened at the bottom to a greater 
extent than the two other holes. A and C were almost perfectly 
identical in shape and depth, and were less than 150 yards apart. 
Of B I have nothing more to say than that its broader and shallower 
form suggested a distinction of some kind which made the amount of 
its affinity to A and C uncertain. In the Zngineer of February 4th, 
1881, sections are given of B and C. ‘The size and shapes of A and 
C are both described in the account given in the Engineer of the 
last-named pit. It is said to have been almost circular in shape, 
‘being 7ft. 8in. in the longest diameter and 6 ft. 9in. in the 
shortest. The sides went down vertically to a depth of 18 feet, and 
had all the appearance of a well or artificial shaft. At the bottom was 
a heap of fallen earth, and when this was removed the sides were 
found to recede, the hole increasing in its diameter to about 14 feet.” 
