270 Proceedings of the Royal Irish Academy. 



Mullau, effected during this withdrawal, the lakes in Glennoo and Donagli- 

 more Glen became confluent. The " Crocknagrally " outlet ceased to operate 

 when the " Aghavoory channel " (W. of hill 651) was initiated. This valley 

 iatakes at about 450 feet, O.D. At this stage the ice swung just clear of the 

 outfall of the channel, and on to the hillside south of Brookeborough. Its 

 position is marked over much of this course by morainic accumulations. 

 Some water escaped over the slightly higher col to the south of hill 651, but 

 this ceased to act as ovei-flow when the •'' Aghavoory channel " was opened. 



On the northern face of Slieve Beagh occurs the finest of these channels. 

 It is a huge glen, beginning at Brown Hill at an altitude of about 500 feet, O.D. 

 It carried some of the drainage of the lakes just described, and would seem 

 to have been in operation during part of the period represented by the 

 Croekuagally and the earlier ovei-flows running along the western flanks of 

 the hiUs. 



A somewhat earlier stage is represented by the small channel which falls 

 east at Carlough. This probably poured its waters into a lake draining 

 by the large valley east of Greaghnagee, likewise falling east. A moraine 

 marking the position of the ice-margin during the formation of these 

 di-ainage channels runs roughly E.-X.-E. from the western end of 

 Greaghnagee. 



A well-marked vaUey, intaking just south of Culla More (844), took the 

 drainage of a lake held up in the valley of the Fury Water. 



All these retreat phenomena of the Slieve Beagh Hills conclusively 

 prove that during the final stages of the glaciation of this area the ice 

 pressure was from the west and north-west, and that ice-free country lay to 

 the east. 



The wide depression of the Clogher valley is choked with morainic 

 material, which has produced countless lakes and influenced the direction of 

 the streams. The ice clearly withdrew across the Clogher valley, W. of 

 Angher, in a westerly direction towards the Eintona Hills. This mode of 

 retreat is proved by the trend of the huge morainic belts running parallel 

 with the axis of the valley, both in the valley itself and on the flanks of the 

 hills to the south, and by the very fine marginal phenomena of the northern 

 flanks of Slieve Beagh. 



Ha\ing retreated from the recesses on the northern slopes of the Slieve 

 Beagh hUls, the ice shrank back with its edge extending in a wide cui"\-e 

 sweeping along the valley. These belts of morainic country can be readily 

 picked out from the hills south of the valley, while among the hillocks 

 themselves their morainic character is no less striking. 



The very extensive ballast pits at Ballyi-addan Hall, just out of 



