2 
DESCRIPTION OP THE ROCKS 
The slate series of the north of England is less complete than that 
of the border of Wales, in respect of the Silurian system, but all the 
other terms are as well shewn around the Cumbrian lakes, as in the 
principality : the whole series dips generally to the S. E. 
1. Upon the granite of Skiddaw forest, rest in succession, first, some gneiss 
and mica schist, then hornblende and actynolite slate, cliiastolite slate, and finally, 
dark clay slate, without the least trace of conglomerate. The hills have a gentle 
outline, and the rills run down in straight lines, and meet at acute angles. 
2. a. On the margin of Derwent water the second system is seen lying upon the 
Skiddaw slate, and presenting new mineral and physical characters. The lowest of 
its beds is a red mottled, apparently fragmentary, argillaceous rock, locally confused 
with porphyritic and amygdaloidal irruptions, sometimes associated with or changing 
to a green brecciated mass, traversed by vertical planes of slaty cleavage. Over this 
is an almost infinite variety of bedded rocks of a green, gray or dark colour, mostly of 
slaty structure, not unfrequently altered in aspect and composition by the local action 
of irrupted igneous rocks, or by a more general effect of pervading subterranean heat. 
Brecciated, amygdaloidal, and subporphyritic rocks, often slaty, diversify this region, 
which includes the noblest and most picturesque mountains, the loftiest precipices, and 
grandest cascades, in the district of the lakes. No organic remains have yet been 
found in it, for comparison with those of Snowdon. 
2. b. It is bounded on the S. E. by beds of limestone containing locally (Coniston 
Waterhead, Broughton) abundance of organic remains, alternating with dark argillaceous 
slates. This is believed to be coeval with the limestone of Bala in North Wales. 
2. c. lhe uppermost member of this system, resting on the limestone, has more 
of the ordinary aspect of grauwacke slate, and is not at all confused by intermixture 
of porphyiitic and other anomalous masses. Its rhomboidal surfaces which strike 
the eye in the country of Hougill fells, and Shap, and in the sides of Windermere, 
and Coniston water, the alternations of massive sandy and laminated argillaceous 
beds, which occur so frequently in these localities, and the general relations of the 
rock, remind us forcibly of the district of the Lammermuir in Scotland ; of the county 
of Down in Ireland ; the Berwyn mountains in Wales ; and parts of the grauwacke 
slates of Devonshire. 
3. a. The Ribblesdale slates, which are presumed to represent this series, will be 
described hereafter. 
