TATE: LAKE COUNTRY ROCKS. 239 
ingredient represented by a chloritic mineral, give to the rock this 
aspect. Northward from this point the gabbro again resumes its 
bedded aspect, from an alternation of coarse with fine-grained 
_ varieties, until we reach the Granophyre that caps the Fell. 
Macroscopically, this closely resembles the Ennerdale granophyre, 
but under the microscope we see that the hornblende of the latter 
is here replaced by augite. The strike of all these rocks, as well as 
that of the Skiddaw granite below at the west end of the Fell, 
coincides with that of the rocks by which they are surrounded. 
A range of hills on the opposite side of the valley east of Carrock 
Fell is built up of bedded contemporaneous basic ashes and lavas 
ejected probably from the Carrock Fell vent. One of the latter has 
marked features by means of which its boulders, though somewhat 
friable, have been identified when widely dispersed. It is a por- 
phyritic diabase, having imbedded in a compact black matrix 
well-defined tabular lozenge-shaped grey crystals of labradorite up to 
an inch across. It may be seen at Berrier or Eycott Hill. Another 
exposure of this rock, at Melmerby, has recently been described by 
Mr. A. Harker, F.G.S. (Q.J.G.S., 1891, p. 517). The Ennerdale 
granophyre, just adverted to, is a closely-grained dirty-pink rock, 
consisting mainly of an inter-growth of quartz and orthoclase, with 
a variable amount of chloritic ingredients scattered therein. 
Buttermere ‘syenite’ is essentially the same rock, but lighter and 
brighter in tint, being nearly free of the ferro-magnesian component. 
It can be obtained near to Scale Force, the ‘Queen of Waterfalls.’ 
Keswick is a good centre for geological work. The wooded 
knoll behind St. John’s Church—Castle Head—conceals two 
quarries in the neck of an ancient volcanic vent, and a complete 
series of bedded intermediate ashes and lavas poured therefrom, 
some 12,000 feet in thickness, forms the eastern’ margin of 
Derwentwater, and may be studied in detail with the aid of Mr. 
Postlethwaite’s concise little book, with its map and section. The 
neck is an ordinary diabase (altered dolerite), of little moment for 
Our purpose ; not so the basement purple breccia of Falcon Crag; 
the altered andesite lava No. 1; the vesicular lava No. 5 in Cat Gill; 
the garnet-bearing lava of Sippling Crag in Shoulthwaite Gill, all of 
which are worth securing for the purposes of identification. The 
‘Green Slate’ building-stone of Keswick is quarried near Grange, 
Borrow rdale; that of Ambleside about Kirkstone. The upper volcanic 
series of pale green and striped slates near Elterwater should not be 
neglected when at Ambleside. The metamorphosed Skiddaw slates; 
chiastolite, andalusite, and mica-schist of Sinen Gill; the Sale Fell 
Minette (the only British rock resembling Phillips’ Dyke, Ingleton) ; 
August 1892 
