272 Proceedings of the Royal Irish Academy. 



influence on the ice of the Ballyreagh Hill and of hill 702 is also clearly 

 brought out by the moraines. 



This effect of hi 11 -barrier and gap is no longer recognisable in the broad 

 belts of morainic country marking the position of the ice-front along the 

 plain. The lobar ridges die down in places where streams, issuing from 

 the ice, have swept away any morainic materials. These gaps are also 

 doubtless in part due to the destruction of the morainic ridges by water 

 escaping from lakes held up by the ice-front against such eai'Her formed 

 moraines. A few low, irregularly-shaped, and winding, connecting ridges are 

 suggestive of eskers. The waters, streaming from the receding ice-lobes in 

 the Glen and Esk recesses, escaped across gaps in the earlier moraines into 

 the valleys which ran down through the breaks in the " Brougher Mountain 

 Eange" into the valley of the Tempo Eiver. The valley of the Glen Eiver 

 carried off the surplus waters from the part of the ice-front immediately to 

 the west of this. Escape by the valleys north and north-west of Greaghrawer 

 was completely barred by the earlier moraines hereabout. On the elevated 

 plain, west of the " Brougher Mountain Eange," these morainic ridges have 

 seriously interfered with the drainage : lakes and turf -flats mark the areas 

 deficient in drainage. 



Similar lines of morainic mounds and ridges, pivoting on the hills at 

 either end, swing across the recess south of Trillick. The different bauds 

 are separated by small turf-flats. TTie arrangement of the ridges indicates 

 a thrusting into the embayment from the west and a withdrawal in the 

 same direction. With further retreat the ice-front was more or less 

 straightened out, the ice finally resting against the Jiillside and depositing 

 one large and continuous moraine. 



4. The Fintona Hills. 



Well-developed moraines run obliquely across the mouth of the embay- 

 ment north-east of the Trillick recess. The ice, represented by these features, 

 held up a lake which discharged by a direct channel into the upper part of 

 the Tempo valley. This outlet, the intake of which is about 700 feet, O.D., 

 forms on the col a broad, flat-floored notch, cut in rock. 



A similar series of moraines runs across the large embayment south-east 

 of Fintona, exhibiting a pronounced conve.xity towards the south.^ Their 

 composition is revealed in several places, e.g. just south of Fintona, where 

 the sands and gravels, sliowiug rude but distinct stratification, are indicative 

 of the swift and changeful currents near the edge of the ice. These moraines, 



• The best of these occurs on the western side of the valley and to the north of 

 Mountstewart. 



