Page:Transactions of the Geological Society, 1st series, vol. 3.djvu/144

 as Subordinate beds in this granitic formation; Since on the shore at Glass Drummond, a ledge of porphyritic syenite, evidently connected with the granitic mass of the adjoining mountain, is seen running out into the sea.

If the granitic formation, above described, be identified with the newer granite of the Wernerians. it may be conjectured that it reposes on mica slate.

Has not been noticed as occurring within the district now described, although the mica slate in the north—cast of Antrim sometimes assumes a character which it is not easy to distinguish from that of this rock.

Of all the primitive rocks mica slate appears to be the most widely distributed over the north of Ireland.

In Armagh, the sides of that narrow valley which separates Slieve Gullen from the Slieve Girkin moutains, and contains the small lake of Cum Lough, are principally composed of mica slate.

In the north-eastern angle of Antrim, mica slate forms the prevailing substratum through a district comprising about 40 square English miles. and extending from north-west to South-east, between the mountain of Knocklead (mouth of Ballycastle) to the valley of the little river of Glendum, which empties itself into the sea at Cushendon, on the north side of Red Bay.

Within this district, however extensive deposits of very recent