234 
THE DOVER COALFIELD. 
Oct., 1890. 
a depth of 310m. Reducing these to section, according to 
scale, a gradual sinking of the beds is shown as they recede 
from the Ardennes, and it is also proved that no coal is found 
to the north of the known coal basins. The same facts are 
also proved in regard to the Liege coalfield. The writer of an 
article in the Builder , to whom I am indebted for some of the 
facts I have recorded, observes that “ the evidence is clear 
as to the connection which exists between the Palaeozoic rocks 
of the Ardennes axis and those of the Somerset and South 
Wales areas/’ and he appears to think that the deterioration 
of the Carboniferous rocks to the north of the Valenciennes 
coalfield, and the appearance of Devonian strata both to the 
north and to the south of the narrow zone to which they are 
reduced, do not hold out much hope of the.existence of any 
large area of workable coal measures on this side of the 
Channel in the south-eastern counties, although of course 
there is “the possibility of isolated portions of the old coal¬ 
field being preserved in folds of the disturbed Palaeozoic rocks, 
whose presence has been proved,” as we have seen, in the 
eastern counties and near London. 
The line of strike of the Carboniferous beds in the Boulon- 
nais would suggest, he says, that “ if the coal measures of 
that area are continued under the Channel, their greatest 
development would be found to the westward of the sinking 
that has been made near Dover. Such a sinking might be 
undertaken about ten miles to the south-west of that place.” 
The section obtained at Dover, close to the Channel Tunnel 
heading, is made up of the following rocks :— 
Chalk 
Lower Grey Marl 
Glauconitic Marl \- 500ft. 
Gault 
Lower Greensand 
Portland 
Kimmeridge 
Corallian 
Oxford Clay 
Kelloway 
Bath Oolite 
Coal Measures 
Sandstone, Clavstone • 20ft. 
Shales, Clays 
Coal struck at 1,204ft. 
In bringing this paper to a close, I have to acknowledge 
my indebtedness for the facts which I have recorded to the 
article in the Builder , to which I have alluded, also to a short 
660ft. 
