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an area which measures about six miles from east to west, and five 
miles from north to south, being rather more than one-third of the 
area under consideration. Of the remaining two-thirds, on which 
the granite has not produced any change, there are portions which 
have been subjected to a considerable amount of lateral pressure, 
the slate being tilted, crumpled, and cleaved; indeed, the once 
horizontal beds may now be seen in a vertical position, or inclining 
at any angle between the vertical and the horizontal. In some 
places, however, there is no trace of cleavage, and the slate splits 
readily along the bedding planes. 
The volcanic rocks on the northern margin of the Skiddaw group 
of mountains consist of ancient lavas and ashes which have 
undergone a considerable amount of alteration. The materials 
composing these ash beds and lava flows may have issued, either 
from the great vent near Keswick or from a subsidiary vent 
situated somewhere between Eycott Hill and High Pike, and the 
beds as they now exist probably represent the remains of a covering 
which once overspread the whole of the Skiddaw group, and may 
have extended some distance to the north and west of it. Near 
the eastern end of this belt of volcanic rock, and adjoining the 
Skiddaw Granite in the lower part of the Caldew valley, there are 
several intrusive masses of felsite, diorite, and gabbro. The felsite 
occupies a considerable area on the top of Carrock, and a somewhat 
smaller area on Great Lingy. It is a coarsely grained felsite, of a 
pale red or brownish-grey colour, with scattered greenish crystals 
which show a spherulitic structure. Between Brandy Gill and the 
summit of Carrock there is a mass of diorite composed chiefly of 
felspar and hornblende, highly crystalline, and rather coarse 
grained. At the north-western end of the diorite, near the head of 
Brandy Gill, there is a small exposure of granitic rock in which the 
crystallization is imperfectly developed. Below, and to the east 
of the spherulitic felsite on Great Lingy, and below the same rock 
on Carrock, there is an exposure of gabbro, the base of which 
consists of large crystals of opaque white felspar (plagioclase) and 
interstitial quartz, and through it are scattered crystals of dark 
olive-green diallage, a mineral very nearly allied to hypersthene, 
