Page:Quarterly Journal of the Geological Society of London, vol. 26.djvu/838

 side of Glencoin Park, there comes on a well-marked band of slates and ashes, the inclination of which appears to be northwards. This would render it probable that the synclinal axis which crosses the vale of St. John is prolonged eastwards as far as Dockwray ; but there are no signs of these slates to the north of Dockwray.

VI. Lower portion of the Green-slate Series in Eycott Hill.

Leaving the main area of the Green Slates and Porphyries for a moment, an excellent exhibition of the lower part of this group is afforded in a rugged hill, known as Eycott Hill, about a mile and a half to the north of Troutbeck Station. North of Troutbeck Station for some distance the country is undulating and moory, and the stream-sections exhibit nothing but drift. There can be no question, however, that this area is occupied by the Skiddaw Slates, since these are seen close to the Station, striking in this direction, and dipping N.N.W. at 50°. When Greenah Moss is reached, a low range of craggy hills commences, trending N.W. and S.E. These are composed of green slates and porphyries, which begin near Greenah Crag, rise in the centre into Eycott Hill (1131 feet), and sink again towards Murrah.

The general structure of this range is well exhibited in a little stream which flows down from Eycott Hill, and which displays the following sequence of beds in ascending order : —

1. Bedded felspathic ashes, 3 or 4 feet in thickness.

2. A porphyritic trap, containing small crystals of felspar, about 20 feet.

3. Bedded felspathic ashes (about 15 feet), dipping S.E. at 30°.

4. A magnificent bedded amygdaloidal and porphyritic trap, sometimes rudely columnar. The base of this beautiful rock is composed of fine-grained dark-green matrix, with numerous specks of hornblende. Scattered through this are very numerous and large crystals of a light-green or olive -coloured felspar, the length of which varies from £ up to as much as 1/2 an inch. The whole rock exhibits also a considerable number of amygdaloidal cavities, some of which are filled with calc-spar, whilst others contain silica in a form nearly approaching to opal. Some of the larger vesicles are filled centrally with calc-spar, with an outer covering of chalcedony.

5. Compact felspathic trap, dark green in colour, and containing many long crystals of glassy felspar.

6. Ashy beds, in part conglomeratic, with pebbles of trap.

7. Amygdaloidal ashes, the cavities of which are sinuous and drawn out, and are filled with chalcedony, calc-spar, or some hornblendic mineral. The matrix of these beds appears to contain a small quantity of carbonate of lime, as it effervesces slightly with acids.

8. A series of bedded felspathic traps, usually containing numerous minute crystals of felspar.

The further sequence of the rocks in this section is now hidden by the Scar Limestone, which comes on close to the road between Berrier and Murrah. The entire length of the section is little short