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breccias, alternating with sheets of lava; the whole being traversed 
by dykes and masses of igneous rock. Of the last named, two 
masses, namely, the Ennerdale Syenitic Granite and the St. John’s 
Quartz Felsite are on the course of the fault which separates the 
volcanic rocks from the main area of the Skiddaw Slates, and it is 
probable that the fault was the channel through which the materials 
composing these masses welled up from beneath in a molten state, 
not to the surface, but into huge caverns formed by the folding 
and crumpling of the strata, which took place during the earth 
movements that produced the fault. The condition of the quartz 
which constitutes an important part of nearly all the igneous rocks 
of the district, proves that they were solidified under great pressure, 
and at a considerable depth beneath the surface. 
The Ennerdale Syenitic Granite occupies an area of about 
twenty square miles, extending from Buttermere on the north, to 
Wastwater on the south. The rock is generally of a pale red 
colour, sometimes changing to dark grey, and it is fairly uniform 
in appearance. It consists of pink felspar (plagioclase and ortho- 
clase), dark green hornblende, and transparent quartz. Usually it 
is very hard, but on the mountain tops it is much decomposed, 
often crumbling into a coarse sand. 
The St. John’s Quartz Felsite is exposed in two masses of about 
equal size, they occupy both sides of the lower end of the vale of 
St. John, and are, in all probability, connected beneath the alluvium 
which forms the floor of the valley. The masses each measure 
about a mile from north to south, and from half to three-quarters 
of a mile from east to west. The colour of the felsite is generally 
light grey, but in some places it assumes a reddish tint. It consists 
of microline and orthoclase felspar, quartz, calcite, and schorl; also 
some epidote and serpentine, part of the last named has probably 
replaced mica. The rock is usually well jointed, and contains 
large fragments that have been much altered. 
The Eskdale Granite is the largest exposure of igneous rock in 
the Lake District, covering an area of about thirty-five square miles. 
It lies at the south-western margin of the area occupied by the 
yolcanic series, and is succeeded on the western side by New Red 
