Page:Transactions of the Geological Society, 1st series, vol. 2.djvu/57

Rh On the slope both of South Bor-roilva and Cronk-ne-liry-Lhaa, in the southern part of the group of mountains, occur abundant blocks of rather decayed granite, composed of yellowish and white felspar turning to a state of earth, and disseminated plates of white mica. The texture is loosened to such a degree that large fragments often yield under the pressure of the hand.

I traced blocks of the same granite in Glen-Moy, though the bed of the stream is hollowed out in the grey-wacke formation.

The central stone of a Druidical barrow in Kirk Ballaugh, is a small grained granite of white felspar, quartz, mica, and a great deal of hornblende.

A vast number of blocks of mica-slate exist on the slope of Slieau-y-Carnane, another hill in the southern district of the group. The quartz is finely granular, and has a silky lustre, which it probably derives from a superficial covering of talc. The plates of mica are white and sparingly dispersed, sometimes crystallized.

I met at the village of Craig-neash with a large settled block of mica-slate. The quartz is of a dirty-grey colour. The plates of mica very few and falling into decay.

Very numerous blocks of this rock occur on the beach at Aire-point. The basis is compact felspar of a flesh-red colour, turning