600 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [June 22, 
thickness of the series is more than some 5000 or 6000 feet, though 
it doubtless varies considerably in different parts of this area. 
It is the object of this communication to describe shortly some of 
the sections in the lower portion of the series of the green slates, as 
indicating the general lithology of the inferior division of the group. 
For this purpose I shall confine myself chiefly to the sections which 
are exhibited between Ulleswater and Derwentwater. 
I. Lower portion of the Green Slates and Porphyries in Borrowdale. 
The whole of the western side of Derwentwater, to the south of 
the little wooded hill called Rosetrees, is composed of the Skiddaw 
slates, which dip persistently to the 8.S.E., at angles of from 40° to 
60°, through Cat Bells, Barrow Side, Maiden Moor, and Narrow Moor, 
to abouta mile to the 8.8.E. of Manesty, near a farm-house called 
the Hollows (fig 1). The Skiddaw slates also form the flat ground 
at the head of the lake, extending as far south as the village of 
Grange, and occupying a narrow strip of ground on the western side 
of the river Derwent. The Skiddaw slates are succeeded to the 
south by the lowest member of the green-slate series, which is well 
exhibited in the northern end of Low Scawdel, to the east of the 
Derwent, and in Grange Fell on the west. It is a massive, dark 
green, compact, and fine-grained felspathic trap, in places rudely 
columnar, and exhibiting no distinct crystals of any kind. This 
trap is directly overlain by a great band of slates and breccias, which 
have been worked on both sides of the river in various places, and 
which form Goat Crag, Castle Crag, and the southern end of Grange 
Fell. The largest quarries are a little to the north of the Bowder 
Stone. Wherever they have been worked these slaty beds are seen 
really to be a cleaved felspathic breccia, of which some beds are so 
fine-grained as to lose their brecciated nature ; whilst others consist 
of numerous angular fragments, from a quarter of an inch in 
diameter upwards, imbedded in a light-green felspathic matrix. 
The fragments in the breccia are mostly of felspathic ash or trap ; 
but many are very like pieces of Skiddaw slate. Subordinate to the 
bands of slate and breccia are some minor beds of trap, one of which 
near the Bowder Stone exhibits numerous small veins of epidote. 
The highest beds of the whole of this slaty series are amygdaloidal 
ashes, the cavities of which are mostly filled with quartz. 
A similar sequence of rocks is exhibited a few miles to the S.W., 
in the valley of Gatesgarth Beck, which flows into the head of 
Buttermere. In proceeding from the head of Buttermere into 
Borrowdale, by way of Buttermere Hawse, the lower portion of the 
Gatesgarth valley is found to be occupied by the Skiddaw slates, 
which dip 8.8.E., at from 50° to 60°, forming Buttermere Fell and 
the N.W. end of Honister Crag. At Dale Head.the Skiddaw slates 
are succeeded by the lowest member of the green slates, in the form 
of a fine-grained dark-green felspathic trap, rudely bedded, and 
crossed at one point by a nearly vertical dyke of intrusive greenstone. 
This is overlain by a great series of cleaved felspathic ashes, amyg- 
