412 MAJOB A. E. DWEBEYHOTISE ON THE [vol. lxxix,. 



and contains two small lakes the overflow from which, a mere 

 trickle, is rapidly lost in the talus in The Cellar, and is the only 

 drainage now passing this way. 



On the northern spur of The Round Mountain, at a level of 

 650 feet, is a well-marked channel 30 feet deep, which carried the 

 drainage through the spur to the western side of The Round 

 Mountain, thus lowering the level of the Ballymakellet Lake, and 

 rendering The Cellar channels inoperative. The drainage from 

 this channel, and later, the direct overflow from the lake, cut an 

 enormous compound channel through the western flank of The 

 Round Mountain, the eastern and original intake being at 490 feet,, 

 and the western and later one at 460 feet. The lower end of the- 

 combined channel cuts the 200-foot contour. 



By the time that this channel had been opened the ice had 

 retreated from the southern flank of Slievenaglogh, and the lake in 

 the Jenkinstown valley (see below) had ceased to exist. This is- 

 proved by the fact that this channel, and also all the later channels- 

 next described, drained into the open country south of the moun- 

 tains, and thus into the Irish Sea. 



The Round Mountain throws out a spur towards the south-east,. 

 and this is cut hj two very large ' gash-channels ' at 410 and 

 350 feet respectively. These channels reach, but do not cut 

 through the crest of the spur, and are similar in origin to those 

 described on p. 411. 



The lowest of the overflows of the Ballymakellet Lake is between 

 Trumpet Hill and the hill (300 feet) east of it. The channel 

 is very large, being 200 feet deep, and must have been operative 

 for a long time. Its period of activity continued until the glacier 

 had retreated beyond the northern end of Trumpet Hill, as the 

 channel can be followed in the low country below the 100-foot 

 contour to the neighbourhood of the moraines near Bellurgan 

 Station. 



The channels above described as hying between The Castle and 

 The Round Mountain drained into the valley between The Round 

 Mountain and Slievenaglogh, which was also occupied by the waters 

 of a lake. This, which may be called the Jenkinstown Lake, 

 from the name of the townland in which it occurred, drained over 

 the col at the head of the valley, cutting an enormous channel 

 which carried its waters into Grlenmore. This Mullaghattin channel 

 is at a level of about 550 feet, at the watershed between the 

 southward flowing stream and the headwaters of the Little River 

 which now occupy the channel. North of Mullaghattin the 

 channel is cut deeply into the solid rock ; but, after turning south- 

 eastwards into Grlenmore, it continues as a definite wide channel 

 in the drifts of that valley, down to a level of 200 feet. 



It will thus be seen that the western, or Tyrone, ice which pro- 

 duced the lake phenomena described above, must still have stood 

 against the southern shoulder of Slievenaglogh up to about 

 600 feet, so as to impound the waters of the Jenkinstown Lake, at 

 a time when the southern spur of Barnavave was clear of ice down 



