^03 Proceedings of the Eojial Irish Academy. 



floor of this great glen ; the moss flat in the bottom of the \alley marks the 

 site of the excavation. 



Considerable drift, in part probably movainic, aeciunnlated lower down 

 ihe valley near Dunlewy, and is now being eroded and deposited as a delta, at 

 the head of Dunlewy Lough, giving this its characteristic straight and flat 

 termination. 



-: Tlie pass at the head of Glenveagh leading to the valley of the Eiver 

 ]?arfa is choked with drift ehai-ged almost exclusively with granite, though 

 it contains also schist and basalt. This col in the rift forming tlie waterehed 

 between the Gleu and Barra rivers would doubtless be considerably lower if 

 . this drift were cleared out, which, to judge from the present activity of the 

 stream, is being rapidly accomplished. 



A glacier passed down Glenveagh parallel with its length until it reached 

 Glenveagli Bridge, wlien, being no longer confined between precipitous walls, it 

 swerved inore to the north and even occasionally to the west of north. Hence 

 the gigantic rocTies moutonnees of Glaek Mountain and Crockawama were 

 overridden by ice flowing due north, while the same trend is indicated by the 

 sea of magnificent rocJics mmdonnecs at the western end of the viaduct across 

 Glenveagh, and by the few drumlins of the neiglibouring area. The drift is 

 composed chiefly of granite, thougli schist and diorite also occui-. 



The ice also proceeded northwards across Barnes Gap, as shown by the 

 numerous striated surfaces and the moutonnee forms of the sun-oundin* 

 nioim tains. 



Small boulders and pieces of schist, quartzite, and .other metamoi-phic 

 rocks were also observed on the southern ^lope and summit of Drumfin. As 

 this area lies within the gi-anit-e boundary, the occurrence of these boulders 

 and fragments demonstrates ice-transport from the metamoi-phic countiy of 

 the east and south-east. Near the road running along the foot of the eastern 

 flank of Stragaddy Mountain, south of Barnes Gap, numerous small bouldei-s 

 of limestone, diorite, schist, and quartzite were encountered, in addition to 

 granite, wliich forms the subjacent rock. Quartzite, scliist, and diorite of^cur 

 in the. drift at Owencarrow Bridge and, as just mentioned, ia the country 

 west of this river. At Glenveagh Bridge the drift is chiefly ehai-ged with 

 granite, together with coarse and foliated diorite (very common), bouldere.of 

 basalt (the larger frequently showing spheroidal weathering), and a few 

 pieces of schist. The same assemblage was found further up the glen at the 

 debouchure of the valley running from Inshagh Lough, and in several places 

 in small exposures aloug the road leading- from Glenveagli to Garton LQua^li. 



These and other occuiTenees, which have not been detailed, of schist and- 

 Other metamoi-phic erratics in the granite country,, do not necessarily imjily 



