42 
Castle Crag (volcanic), and another on the west side of the lake, by 
the flanks of Cat Bells and Causey Pike (Skiddaw slates). The 
difference in the appearance of the two, originating in the different 
structure of the rocks, was very discernible. 
The smooth surface of the Skiddaw slate series was sometimes 
modified by special circumstances—as when the slate contained harder 
sandy beds, standing out in relief, or when masses of eruptive greenstone 
occurred; thus, on the east side of Hindscarth, there was a long patch of 
greenstone, forming a very craggy side to the mountain. ‘The relative 
direction and amount of the true dip and the cleavage dip of the slate 
frequently affected the form of the mountain. To this, probably, was 
due in great measure the shape of Blencathra (Saddleback); the 
gentle slope to the north at the back of the mountain corresponded 
in direction and inclination with the bedding dip, and the fine ravines 
upon the south-east side were produced by the weather along the 
steeper cleavage dip. Other instances of this might be mentioned. 
Glancing at the rocks of the volcanic series, it was found that 
among the mountains of Borrowdale all the variety of rugged and 
craggy aspect was due to hard rocks, and yet rocks of different 
' degrees of hardness. Standing on Stye Head Pass, the connection 
between the grandly rude step-like form of the Scawfell range, and 
the inclination of the massive stratified beds of altered ash forming it, 
dipping at an angle of twenty-five deg. in a S.S.E. direction, and 
traversed by numerous joints and dykes more or less at right angles, 
could be seen. When there occurred a great thickness of ash of nearly 
uniform hardness and well cleaved, the form of ground often more 
nearly approached that of the Skiddaw slates, as along part of the 
summit of Helvellyn. 
The Vale of St. John was a striking instance of the dependence of 
the mountain form upon geological structure. On one side was a long 
range of precipitous mountains with evident lines of bedding running 
along its face, the strata of hardened ash, dipping steadily into the hill 
side at from eight to thirty deg., while on the other side the hill was 
made up of hard beds of trap and softer ash, lying in a long, synclina 
trough faulted at several points: each hard bed formed a prominent 
terrace. The various faults that ran through this district tended often 
to produce marked effects upon the scenery. Not that the actual dis- 
location had given way to gaping fissures, &c., but that rocks of 
various degrees of hardness, having been thrown together along the 
line of fault, the denuding powers had acted unequally upon them, 
One of the most noticeable features in the Lake distriet was the 
