78 SEVENTH REPORT—1837. 
fields of coal. Some of these isolated coal fields are found on the 
summits, others in the valleys, of the subjacent gritstone series, and at 
the western extremity of the transverse ridge of gritstone, the grit- 
stone hills are surrounded with beds of coal. 
At the northern extremity of the Lancashire coal district, the car- 
boniferous strata are found in the form of a large natural basin, whose 
outer edges rest upon the gritstone rocks of Boulsworth Hill, Pendle 
Hill, and Padiham Heights. In the centre of this basin, at the Fox- 
clough Colliery, near Colne, the inclination of the coal beds is very 
gentle, being only 1 foot in 12, and rising on all sides. 
Three miles to the south-west of Colne, at the Marsden Colliery, the 
level of the coal mines crosses the valley of the river Calder, and the 
carboniferous strata rise on each side of the valley towards the grit- 
stone hills, which form its boundaries. 
Very steeply inclined coal mines, called “ rearing mines,” have been 
noticed on the northern boundary of the Lancashire coal district, over- 
lying the gritstone strata to the north-east of Blackburn. Imme- 
diately north of Blackburn, at Shire Brow, the fine quartzose sand- 
stone, of which that hill is composed, dips to the 8.S.E. at an angle of 
about 50°, and the shales and sandstones of the coal measures appear 
at the base of an adjoining hill, dipping in the same direction, at an 
angle of 33°. 
Three miles south-west of Blackburn, red sandstone rock is visible at 
Feniscowles Bridge: it occurs there, in thinly stratified beds, with mica ; 
and at Withnell, south of Feniscowles, the shales and sandstones of the 
coal formation make their appearance nearly in a horizontal position, 
or slightly inclined to the west. 
Associated with the red sandstone strata, many beds of marl are 
found overlying the coal measures on the west and south of the Lan- 
eashire coal field, and concealing the boundary of the carboniferous 
district, so that the western and southern limits are still very imper- 
fectly known, except by the operation of mining. 
From the termination of the gritstone strata, near Blackburn, the 
line of coal mines on the western side of the coal district may be traced 
by Mawdesley and Newburgh to Blague Gate, Stanley Gate, and 
Bickerstaffe. South of Bickerstaffe, coal is found under Rainford 
Moss; in the same neighbourhood, coals were formerly worked south 
of Knowsley Park, and west of Prescot; and coal shales have been 
found under the sandstone strata at the Hazles, near Prescot. 
The south-western extremity of the Lancashire coal district is si- 
tuated in the neighbourhood of Tarbock. At Whiston, north-east of 
Tarbock, the carboniferous strata are visible on the line of the Liver- 
pool and Manchester Railway. North of Whiston, and beyond Prescot, 
the beds of coal are cut off by the intervention of a large mass of red 
sandstone rock, nearly a mile in width; coals are worked again to the 
north of this sandstone rock at Gillar’s Green ; and the coal measures 
appear to be again interrupted, on the north-east of Prescot, by another 
portion of the red sandstone formation, which extends, in a northerly 
direction, beyond Eccleston. 
