276 Proceedings of the Royal Irish Academy. 



ment of the moraiuic ridges,^ by the marginal drainage phenomena, and by 

 the eastward diversions of the streams along the hill flanks. This latter 

 feature is clearly recognisable in the streams draining the southern flank of 

 PolLnalaght. 



A series of roughly parallel morainic belts, skirting either side of the 

 plain, marks the lateral moraines of tliis great Fintona Glacier. They are 

 especially well deA'eloped along its southern edge, e.g. south of Fintona and 

 of Seskinore, and on the northern side along the south-east flank of 

 Pollnalaght. Trillick lies in a hollow between two such moraines. Farther 

 east, very fine moraines occur at Beragh and south of Six Mile Cross,^ where 

 they form pronouncedly undulatory belts of country. 



The drainage from the ice, which deposited these lateral moraines, escaped 

 on the south by the " Seskinore channel," and on the north by its equivalent, 

 the Dooish valley. Springing out of these lateral ridges are the terminal 

 moraines.' Of these, the finest leaves the lateral at Seskinore curving away 

 to the north as a very broad, billowy strip of country ; ■• others are clearly 

 developed north of Fintona. They all exhibit a convexity to the east. These 

 morainic arcs are separated by turf and ri\'er flats and numbers of lakes. 

 Though for the most part fairly regular in their development, they not 

 infrequently coalesce over short lengths, only to diverge again at some little 

 distance. 



The lateral moraines are crowded together into comparatively narrow 

 strips which margin the plain ; the spaces between the separate drift ridges 

 gradually widen as they pass into frontal moraines along the median line of 

 the plain. 



Great gravel spreads occur where the frontal moraines spiing out of tlie 

 lateral ; upon such lie the grounds of Seskinore House and Ecclesville, near 

 Fintona. 



The melt waters from the ice-front, at the different stages of the retreat, 

 were largely carried off by the valleys, formed successively between the 

 retreating ice-face and the last-formed moraine, and which are now 



' Though very regular in form, as drawn on the map, small irregularities are by no 

 means uncommon, but are not reproducible on this scale. 



- These features, described as terraces, are sketched in the Mem. Geol. Survey, Sheet 34, 

 pp. 21, 22. 



2 The position of some of these is brought out by the contours, and by small peripheral 

 streams running in the valleys between the morainic ridges, e.g. S.-W. of Omagh, E. of 

 Bundoran Junction, X. of Fintona, and If.-E. of Dromore. The Quiggany Water, which 

 flows X. from Fintona, follows the course of the moraines ;the Oweureagh,on the contrary, 

 cuts across several. In other cases, and these the majority, contours fail to bring out 

 the features. 



^The ridges around Dromore are chiefly "solid " features. 



