REMARKS ON THE COAL DISTRICT, ETC. 427 
overlying the gritstone rocks of the Northern 
boundary. 
Red sandstone strata occur three miles to the 
South-West of Blackburn, at Feniscowles-bridge ; 
and the red sandstone formation may be subse- 
quently traced, with its associated rocks, on the 
Western and Southern limits of the Lancashire 
coal district. 
A remarkable circumstance occasionally attends 
the junction of the red sandstone formation with 
the coal measures of South Lancashire. Long 
promontories of red sandstene are there found to 
divide, to a considerable depth, the strata of the 
coal measures ; they sometimes narrow gradually 
towards a point, nearly in an acute angle, within 
the coal formation, and then spread out, in the 
opposite direction, beyond the limits of the carbo- 
niferous rocks. 
Several of these promontories of red sandstone 
have been observed on the Southern boundary 
of the Lancashire coal district, in the neigh- 
-bourhood of Eccleston, and Worsley, in South 
Lancashire, but the principal promontory of 
red sandstone which has yet been discovered, 
