part 3] GLACIATION OF NORTH-EASTERN IKELAND. 355 



Armagh. In Armagh the granite becomes associated with other 

 igneous rocks of a more basic type, and forms the complex of 

 Slieve Gullion (1895 feet O.D.) and Carlingford Mountain (1935 

 feet). 



The Mourne Mountains also consist of granite, and form an 

 isolated mass culminating in Slieve Donard (2796 feet) : there are, 

 moreover, several other peaks rising to more than 2000 feet above 

 the sea. 



The high land of the Newry-Castlewellan area and the Mourne 

 Mountains on the one hand, and the Slieve Gullion-Carlingford 

 mass on the other, are separated by the great valley of Poyntzpass 

 and Carlingford Lough, to which reference will be made later. 



II. The Northern Part of the Antrim Plateau 

 (see map, fig. 1, p. 356). 



[1-inch Ordnance Map, Sheets 7 & 8, & parts of Sheets 13, 14.] 



Throughout almost the whole length of the coastline the country 

 is bounded by high, nearly perpendicular cliffs, the exceptions 

 occurring in Ballycastle Bay, at the mouth of the Carey River, 

 near Bushmills at that of the Bush River, in the neighbourhood 

 of Portrush, and at the mouth of the Bann. 



A fault running near the line of the railway from Armoy to 

 Ballycastle divides the district into two regions of notably different 

 relief. The eastern portion extending from Torr Head and Fair 

 Head to Ballycastle and Armoy is a country of marked physical 

 relief, and is drained by the Carey River (with its tributary the 

 Glenmakeeran River) and by the Glenshesk River, the waters of 

 which enter the sea at Ballycastle. 



The Carey Kiver may be said to take its rise on Cushleake 

 Mountain, although the drainage from the slopes of this upland 

 flows first into Loughaveema, and thence underground for some 

 distance before joining the other tributaries. The valley of the 

 Carey River is deeply cut through Glacial clays and gravels, 

 although there is but a thin covering of these deposits on the 

 higher ground of Carnanmore and Carneighaneigh which form its 

 flanks. 



At a point at an altitude of 606 feet on the main road, on the 

 left bank of the stream, there is a thin covering of drift containing, 

 among other erratics, the coarse-grained dolerite of Fair Head ; 

 Carboniferous sandstone probably derived from the lower part of 

 the cliffs above Portdoo, east of Fair Head ; red quartzite ; basalt ; 

 and local schist ; also large pieces of vein-quartz showing striations. 



At a point 100 yards above Corratavey Bridge, in the bed of the 

 Corratavey Burn, is a section of a reddish-brown boulder-clay with 

 a covering of gravel. The boulder-clay contains schist, flint, chalk, 

 basalt, gneiss, vein-quartz, and big boulders of red quartz-porphyiy 

 derived from the country immediately to the east. 



Boulder-clay similar in composition to the last also occurs at 

 intervals over the country lying between the valley of the Carey 

 River and Fair Head, 



