172 
THE DOVER COALFIELD. 
Aug., 1890. 
made in the neighbourhood of London have shown the 
existence of the Palaeozoic rocks at varying depths below 
the surface. Thus, in a boring at Ware the Old Led Rocks 
were struck at a depth of 800ft. and Silurian beds at 1,289ft. 
The rocks of this buried ridge are tilted at a considerable 
angle, corresponding in this respect with the similar rocks in 
Belgium and France and in the Somerset coalfield. At Tot¬ 
tenham Court Road a sinking for water proved the presence 
of Devonian strata at 1,066ft. ; the same rocks were struck 
at Clieshunt, near Turnford, at 980ft. only ; whilst at Rich¬ 
mond the overlying Oolitic beds were proved to be very thin 
(87ft.), the Wealden being altogether wanting, and red rocks 
were pierced which might be either Triassic or Devonian, 
there not being sufficient evidence to show which. Other 
borings undertaken at Streatham, at Crossness, near Erith, 
and at Kentish Town, reached similar rocks at distances 
varying from 1,060ft. to 1,302ft., and further search in this 
area might possibly prove the existence of coal measures. In 
a boring at Harwich Carboniferous beds were found at a 
depth of about 1,030ft., but the coal measures themselves are 
absent, the rocks pierced being of older age, as was proved by 
the presence of Posidonomyse in them. Passing more to the 
south, the Wealden was pierced in a deep boring near Battle, 
and at a depth of about 2,000ft. the rocks were of Middle 
Oolite age, any coal measures, therefore, which might under¬ 
lie these would probably do so at so great a depth as to be 
quite unworkable, even if it were possible to find them. 
If we now turn to the Continent we find that the great 
Palaeozoic ridge which forms the Ardennes Mountains shows 
clear signs of its being a line of upheaval. We find there 
Devonian and Silurian rocks highly tilted, contorted, and 
even inverted and metamorphosed, facts which prove violent 
disturbance, and the coal measures in this district are conse¬ 
quently themselves greatly faulted and folded. The compara- 
tivelv small nortion now left of them lies in a narrow and 
A. 
broken band running from Westphalia, and which rests 
against the older rocks of the Rhine district. 
Let us now trace these coal measures. The Belgian coal¬ 
field consists of a network of basins occupying the folds of 
the older Devonian and Silurian rocks, which mav be traced 
3 %f 
from Prussia into France. 
The Carboniferous formation in Belgium, as in this 
country, has three main divisions, the lowermost being the 
Carboniferous Limestone, the characteristic features of which 
are well seen about Dinant and the Valley of the Lesse, as 
well as in other parts of the country. This limestone is 
