274 JProceedings of the Royal Irish Academy. 



ceases to fall when its floor reaches the 660-foot level, or the height of the intake 

 of Bemisk Glen (B.). This glen is gashed to a depth of some 80 to 100 feet in 

 O.E.S. conglomerate, and falls right to the floor of the Oweubrack Eiver. 

 The approximate grading of the two valleys suggests a free outfall and the 

 location of the ice-front at this stage at least as.far north as Beragh and Six 

 Mile Cross.^ Before the ice had swnug clear of the hill at Foremass, the 

 waters of Bemisk Gleu poured into "Lake Owenbrack " and escaped into the 

 " Seskinore channel " by the valley (F.) along the side of that hill. 



A small valley — " the Cloghfin channel " (C.) — cuts chiefly in drift and 

 intakes at 750 feet. It took the drainage from a small lake held up to the 

 north of this. It falls south to just below the 700-foot contour, or the level 

 of the lake in the Owenbrack valley. 



Huge moraines, deposited high up the hill-slopes, stretch from east of the 

 Fall Brae to Black Bridge in the FaUaghcam valley. Though they were 

 largely destroyed diuing a later phase of the retreat, as their materials con- 

 tributed in great measure to the floor-deposits of " Lake Fallaghcam," enough 

 still remains to make them most stiiking features in the local sceneiy. An 

 earlier formed moraiue, almost equally large, mns to the south of these for 

 about two miles in an east-west direction. The ice-front, when coincident in 

 position with this moraine, ponded back the drainage of the hills to form a 

 large lake which discharged by the direct overflow of Todd's Leap (T.). At 

 this stage, another and somewhat larger lake existed to the south of "White 

 Bridge, cut off from its neighbour by the shoulder of the intervening hill. 

 This lake likewise ditiined into the Clogher valley by a direct channel south- 

 east of Lough Abraddan. The slight retreat of the ice had for its eflect the 

 melting of the two lakes into one sheet, the surplus watei-s of which continued 

 to drain by the lower Abraddan channel ( A . ( :.) . This overflow falls south, and 

 intakes at over 600 feet, OS). Lake-t«rraces corresponding with this outlet 

 occur below Black Bridge. 



The next shrinkage was more considerable, roughly three miles, and by 

 uncovering the watershed between this valley and that of the Owenbrack to 

 the east caused the formation of an extensive lake continuous over the water- 

 shed about the site of Dunmoyle. Its outflow was by the "Abiaddan 

 channel," though some water possibly escaped over the pass leading to 

 Harper's Bridge,' while its floor deposits, consisting chiefly of fine sand, are 



' TMs Is doubtless part explanarion of the great width of the valley of the Owenbrack 

 River below the oatiall of the Bemisk Glen. 



- The floor of this pass is now obscured bj a great expanse of thick turf. The depres- 

 sion doubtless served as an overflow at an early stage before the waters in the F aHacr b- 

 cam and Owenbrack valleys were continuous, and when a small lake existed at the head 

 of the latter. 



