1873.] CAMPBELL — GLACIATION OF IRELAND. 209 



form, which ends in a muddy stream like the rest of its class. This 

 is a model local ice-system. 



Ireland. — On the top of one of the Mourne Mountains are marks 

 which I attribute to a small local system of this kind. The marks 

 are fresh, and a small stream of water runs along the striae down- 

 hill, towards a hollow above Ross Trevor and Carlingford Lough, 

 in which are piles of drift arranged in the form of a terminal moraine. 



Mookish, in the north-east corner of Ireland, is a tall scarped 

 isolated hill of quartz, with a plateau on the top. The shape of the 

 hill is very like that of Eriks JSkull, in Iceland. 



On the sides of Arrigle, near Mookish, are cliffs with talus heaps ; 

 the top is a plateau a few yards square. When glaciers were in 

 Gweebarra a dome of ice certainly stood upon Mookish ; and pro- 

 bably the small remnant of a plateau on the top of Arrigle indicates 

 similar work. 



5. Iceland. — Lang Johull, near Erik's JSkull, is a long hog- 

 backed ridge about thirty miles long, and covered with a sheet of 

 ice. On the western side I could see no bare rock. On the eastern 

 side, riding by Spraenge Sander, I saw that ice moves from the ridge 

 down towards the low lands as water flows down the roof of a house. 



At one place a great rock stands out like a garret-window in a 

 roof. The ice splits at the back, flows down the sides, and meets 

 again below at the base of a cliff. The direction of movement 

 can be seen at a glance. The riven ice looks as if a flood had sud- 

 denly frozen while rushing down the steep side of this long hog- 

 backed ridge. 



The sea-face of the Mourne Mountains seemed to indicate a similar 

 movement at some places ; but I was unable to find striated rocks 

 there. Dun na Cuaich, at Inverary, and Sul Bheinn, in Sutherland, 

 are like this " garret- window " in shape ; and the movement may be 

 seen behind any stone in a moving stream of water. 



Donegal. — The general shape of the hill country about the north 

 of Ireland is a series of irregular furrows and ridges which trend 

 from N.E. to S.W. or thereby. The ridge, on which Snow Moun- 

 tain is the highest point, is bounded on the S.E. by Gweebarra Pass, 

 the deep groove which contains two fiords, several lakes, and two 

 rivers which flow out at opposite ends on opposite sides of Ireland. 



On the north-western side the ridge is bounded by a shorter 

 furrow called Glen Veagh. North of that groove is a broken quartz 

 range with a similar trend, which includes Arrigle and Mookish, 

 standing apart. It may be said that granite disturbed the sandstone 

 and altered it and shaped the country. But what shaped the 

 granite ? 



The Snow -Mountain range, like Lang Jokull in Iceland, sent down 

 a flood into Gweebarra Pass, as I have shown. It also sent off a 

 broad flood northwards. Erom the base of Slieve Snaght water 

 now flows out of a corrie through nearly a hundred lakes, over gra- 

 nite, about eight miles to Dungloe, where a small river enters the 

 head of a short fjord. The whole country is sprinkled with angular 

 blocks of granite, as big as hay-cocks, hay-ricks, and small houses. 



VOL. XXIX. — PART I. P 



