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all the beds of any coal-basin is well known to be so great and 
rapid, that, in the different parts of the same basin, it is often 
difficult, and sometimes impossible, to establish any correlation, 
while in adjacent basins, such as those of Wales and Bristol, or 
of Hainaut and Liege, such attempts have, with few excep- 
tions, hitherto utterly failed. There are, however, general fea- 
tures which serve to show some relationship. The great 
central mass of from 2,000 to 3000 ft. of rock called Pennant 
exists in both the Welsh and Bristol coal-field ; and the total 
thickness of Coal Measures is not very different, being, say, 
10,500 ft. in the one, and 8,500 ft. in the other, with workable 
seams of coal, 76 in Wales, and 55 in Somerset. In the Hainaut 
(or Mons and Charleroi ) basin, the measures are 9,400 ft. thick, 
with 110 seams of coal; in the Liege basin 7,600ft., with 85 
seams; and in Westphalia, 7,200 ft., with 117 seams. On 
the other hand, none of our central or northern coal basins, with 
the exception of the Lancashire field, exceed half these dimen- 
sions, and more generally are nearer one-fourth. Further, the 
difference which exists between the north country coals and 
those of Wales and Somerset, the preponderance of caking-coals 
in the former, and of anthracite, steam, and smiths’ coal in the 
latter, equally exists between our north country coals and those 
of Belgium, which latter show, on the other hand, close affini- 
ties with those of Wales and Bristol. I am informed by two 
experienced Belgian coal-mining engineers and good geologists, 
( who have twice visited our coal districts, that the only coals 
they found like those of Belgium were the coals of South Wales 
and Badstock ; there was the same form of cleavage, the same 
character of measures, and the same fitness for like economical 
purposes. Organic remains afford us little help ; and not 
sufficient is yet known of their relative distribution. The 
plants, are, as usual, the same ; so also are shells of the genus 
Anthracosia , and a number of small Entomostraca ; and the 
marine forms are scarcer than in some of our central and 
northern fields. 
That, therefore, which best indicates the relation between the 
coal-fields of the south-west of England and those of the north 
of France and of Belgium, is the similarity of mass and struc- 
ture, uniformity of subjection to like physical causes, and 
identity of relation to the underlying older and to the overlying 
newer formations. 
These physical features are of much importance and interest. 
Of the underground prolongation of the axis of the Ardennes 
through the south of England there can be little doubt ; nor can 
there be much doubt that the same great contortions of the 
strata which in Belgium folded alike the Coal Measures, the 
Mountain Limestone, Devonian, and Silurian series, and were- 
