Charlesworth— (T^«a'«^ Geology of North-West of Ireland. 273 



transferred to the map (PI. IX), indicate sufficiently well the position of the 

 ice-margin at successive stages of the retreat, and how, during the northerly 

 recession of the ice-front, this became less and less curved, till, to the south 

 of Pintona itself, the moraines become virtually straight. Here again, 

 however, the ice-front and moraines are, in general, in close dependence on 

 the relief. 



Througliout the whole of the withdrawal a temporary lake was held up in 

 this embayment, and discharged by the large valley at the head of the recess. 

 The intake is at 4S9 feet, O.D. Another well-developed channel begins 

 north of Crockard, and falls east, having been produced by tlie drainage from 

 a lake in the small embayment to the west, 



Eoughly similar again is the arrangement of the moraines in the large 

 recess extending south-east from Seskinore. A series of morainic ridges spans 

 the valley. The finest swings across the valley from the eastern flanks of 

 .the Crooknatummoge hills over Kaveagh and Eskragh to the south of the 

 Fall Brae. 'J'his is the same moraine which is best developed in the " Fintona 

 .recess," and of which mention has just been made. This serves as a 

 useful datum-line for the correlation of the other morainic features. 



The ice, which formed these moraines, likewise impounded a lake — " Lake 

 Seskinore " — -in this large embayment ; its surplus drainage escaped by an 

 overflow valley (S.), largely preglacial in origin, yet, perhaps, unsurpassed in the 

 whole region dealt with in this paper.' It enters the Clogher valley to 

 the north of Clogher, is practically streamless, and some 400 yards in width ; 

 ■its flat floor falls very steadily and gradually southwards from its intake 

 at about 350 feet, O.U. Its size greatly exceeds that of the valley to the 

 west, to which reference has just been made. The difference is clearly not to 

 be ascribed merely to the extent of the lakes which were drained by the two 

 valleys. The " Seskinore channel " was the means of escape of the waters 

 which poured from all the higher lakes held up in the recesses in the hills 

 ■to the east of this as far as Carrickmore, some twelve miles distant. 



A series of lakes was impounded in the valleys south of Carrickmore. 

 -A fine dry valley (A.) was observed at the head of the Altmore Eiver, which 

 carried off the waters of a lake held up about Altmore Lodge; the great 

 accumulations of well water-worn sands and gravels at its head doubtless 

 represent a moraine formed about this time. The small overflow channel (I), 

 falling east, located just south of Inishative, was formed by the ponding of 

 the Altanagh Eiver. 



Bara Glen (E.G.), a cross contour valley, intakes at about 750 feet, O.D., and 



' Reference is made to this valley in Geological Survey Memoir, Sheet 46, p. 6. 



