146 DAVIS : SOURCE OF BOULDERS IN CALDER VALLEY. 
was formerly very extensively used for burning to obtain 
lime. The remains of lime-kilns may be seen studding the 
hill-sides throughout the locality. In the valley with 
Burnley for its centre, the remains of glacial origin occur 
frequently. The gravels in the valley of the Yorkshire 
Calder may have been derived originally from the boulder 
beds in these districts, but a glance at the physical features 
of the district renders this view of the case somewhat pro- 
blematical. The distance from Todmorden to Burnley is 
9J miles. The two Calders rise at Calder Head, four miles 
from Todmorden. The valley of the Yorkshire Calder, 
running south-eastwards, is narrow, rugged, and falls rapidly 
from a height of more than 700 feet above the sea-level at 
the summit, to about 380 feet at Todmorden. On either 
side the valley the ground rises rapidly, and is surmounted 
by precipitous escarpments of sandstone. The Pennine 
fault runs in a line with the valley, and has displaced the 
rocks, so that those on the Lancashire side are composed of 
the third grit, the opposite one being thick beds of the 
Kinderscout grit. Surmounting the latter, the picturesque 
groups of weathered rocks, the Bridestones and Hawkstones, 
ornament the sky-line. Near the source of the stream the 
Lower Coal Measures set in, and the sides of the valley 
being, in consequence, of a much looser and more friable 
nature, landslips have resulted, producing a great number 
of rounded hillocks. The Lancashire Calder rises and runs 
in a similar narrow valley, falling with equal or still greater 
rapidity in the opposite direction, the bed of the stream at 
Burnley being 350 feet below that of its source. Beds of 
gravel are occasionally exposed in the sides of the stream, 
as at Walk Mill, two miles from its source, and 200 feet less 
in elevation, where, beneath a bed of peat principally com- 
posed of the remains of hazel trees, there is a rough sandy 
gravel. The contained stones are for the most part semi- 
