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POPULAR SCIENCE REVIEW. 
plants, &c. It indicates shallow-sea conditions, and although 
in marked contrast in this respect to the deep-sea chalk for- 
mation, yet no positive evidences of unconformity, to indicate a 
lapse of time, exist between the two. 
Eesting upon the Thanet sands, we find, throughout the 
London basin, a series of sands, mottled clays, and pebble-beds, 
to which. the name of Woolwich and Beading beds has been 
applied by Mr. Prestwich. Under London the beds are from 
80 to 90 feet thick. The best known section is that at Charl- 
ton, near Woolwich, where the beds rest on the Thanet sand, 
and are overlain by the Oldhaven beds. 
At G-reenwich, the Woolwich and Thanet beds are faulted 
against the chalk, there being a downthrow on the north of 
about a hundred feet. (See Section.) North of London, 
the Hertfordshire puddingstone, a well-known rock, is formed 
by the consolidation of the pebble-beds of the Woolwich and 
Beading series. This was to be seen three years ago, in a pit 
near New Organ Hall, east of Badlet’s station on the Midland 
Bailway 
The fossils of this series show that the conditions of the 
area varied, the mollusca sometimes indicating estuarine, 
at others purely marine conditions. Besides the mollusca, of 
which the species are numerous, many fish remains occur; 
bones of turtles and scales of crocodiles have been found at 
Dulwich, as also remains of a tapir-like animal called the 
Coryphodon. 
The Oldhaven beds, so named by Mr. Whitaker, consist 
chiefly of rolled flint-pebbles in a sandy matrix, and are locally 
developed south and east of London, with a thickness of about 
20 feet. In the immediate neighbourhood they are best seen 
at Bromley, Croydon, and Blackheath. Mr. Whitaker con- 
siders that these beds were not formed as a beach along a 
chalk-shore, as in that case they should contain many flints 
but partly worn ; and he is led therefore to infer that they 
must have been deposited some way off the shore, as a bank to 
which no flints could get without having been long exposed to 
wearing action. They contain many species of mollusca, some 
fish, and bones of turtles. 
Above these Oldhaven beds comes the London clay, a deposit 
which is probably the most familiar to Londoners. It consists 
of brown and bluish-grey clay, with occasionally bands of sep- 
taria or cement-stones ; these latter, which are dredged off 
Harwich for the manufacture of cement, and which occur in 
great numbers on the shore at Southend, are composed of 
clayey limestone with divisions or septa of carbonate of lime. 
According to Mr. Whitaker, in the neighbourhood of London, 
its thickness averages 420 feet. Sections are common in the 
