302 DWERRYHOUSE : COAL MEASURES AND MILLSTONE GRIT. 
Accordingly we find some of the channels filled in with 
shales containing thin bands of Carbonaceous material (Fig. 1). 
It would thus appear that the change of conditions came 
on very rapidly at this point, and it may be that here we have 
the fossil impress of the last tide, or perhaps the last flood that 
passed over this part of the Millstone Grit delta. 
The general relation of the rocks will be seen from Fig. 2. 
Coal Msasv^es. 
A bed of coarse grit, closely resembling the Millstone Grit 
below, occurs about 15 feet up in the Coal Measures. It is about 
five feet in thickness and indicates that there were occasional 
recurrences of the conditions under which the grits were formed. 
The presence of thin coals in the shales of the Millstone 
Grit series, and of coarse sandstones in tlie Coal Measures, 
shows that there was really no sudden change in the conditions, 
but merely a gradual passage from outer estuarine to landward 
swamp. 
My thanks are due to Messrs. B. Wliittaker & Sons for the 
facilities which they have kindly given me in the examination 
of this interesting section, and I hope to be allowed to follow 
up the workings in order to ascertain if any further light be 
thrown upon the matter as the excavation proceeds. 
