Charleswohth — Glacial Geology of North- West of Ireland. 175 



excepting the hilly tract lying south and west of the Eiver Erne, Lough Ei-ne 

 and Upper Lough Erne. It includes the whole of the county of Donecfal, the 

 greater parts of the counties of Tyrone and Londonderry, and small portions 

 of the counties of Fermanagh and Monaghan. It embraces some 4,300 sq. 

 miles. 



The field work occupied portions of four successive summers, and many 

 odd weeks at other seasons of the year, amounting in all to close on 80 weeks. 

 It is not suggested that this work by any means exhausts the glacial geology 

 of the north-west of Ireland. It may, however, be claimed that the leading 

 features of the glaciation and the movements of the different ice masses in 

 space and time have been determined. The outlining of this framework now 

 renders possible the intensive study of any small part of the country. 



A preliminary account of the main conclusions arrived at in this work was 

 given at the Cardiff Meeting of the British Association in 1920 (" Eeport," 

 p. 357.) 



The research was entered upon because of the difficulty which I 

 experienced in accepting the current theories of the glaciation of the north- 

 west of Ireland as originally enunciated by E. Hull ^ and J, E. Kilroe- — a 

 scepticism due in part to a recognition of the empirical manner in which those 

 results had been arrived at, and in part to the impossibility of reconciling 

 them with my cursory and meagre knowledge of the glaciation of Donegal ; 

 a more extensive knowledge of the country and its glaciation has amply 

 confirmed the suspicions then entertained. 



It was at first intended to confine the examination to the Highlands of 

 Donegal as the crucial area where these glacial theories could be put to the 

 test. As the work progressed, however, and the importance of the Donegal 

 ice gradually revealed itself, it was found necessary to thrust the limits of the 

 research ever eastward and southward. 



II. — Bibliography akd Cuerent Theory. 

 The literature dealing with the glaciation of the north-west of Ireland is 

 singularly scanty. The drifts of the local districts have been very briefly 

 described in the Memoirs of the Geological Survey of Ireland dealing with 

 these areas, to which reference will be made in this paper as occasion 

 arises. The wider problems and correlations have been considered by but 

 few writers, prominent among whom are Maxwell Close, Carvill Lewis, J. R. 

 Kilroe and E. Hull. 



' Physical Geology and Geography of Ireland, 3rd ed., 1891. 



■ Directions of Ice-Flow in the North of Ireland, as determined by the Observations 

 of the Geological Survey. Quart. Journ. Geol. Soc, xliv (1888), pp, 827-833. 



[2 £ 2] . 



