pjart 3] glaciation of north-eastern Ireland. 421 



^actual accession of power on its own part, there is insufficient 

 •evidence to show. 



The great morainic system extending from Ballynioney to 

 Glenshesk, with its correlated overflow-channels and lakes, the 

 spreads of outwash-gravel in the valley of the Bann at Macfin, 

 and the boulder-clay and gravels with Liassic materials at 

 Drummaquill belong to this stage. 



I tender my thanks to Mr. R. J. Welch, M.R.I. A., and to 

 Mr. Robert Bell, F.M.S., who have frequently placed their intimate 

 knowledge of the area at my disposal, and to many members of 

 the Belfast Naturalists' Field-Club for the use which I have made 

 •of their records of erratics. I wish also to thank Prof. J. K. 

 'Charlesworth for information which he has from time to time 

 given me with regard to the progress of his work on the glacial 

 geology of the district to the west of that described in the present 

 paper, and for his valuable suggestions and help when we traversed 

 ^oarether the borderland of the two areas. 



EXPLANATION OP PLATES XXIII & XXIV. 



Plate XXIII. 



"View looking- northwards down the Loughayeema Channel. (See p. 360.) 



Plate XXIV. 

 Altiffirnan Glen, Carneighaneigh in the distance. (See p. 361.) 



Discussion. 



Mr. Gr. W. Lamplugh congratulated the Author upon the 

 results of his wide investigation, which had thrown much new 

 light upon the glaciation of North-Eastern Ireland. The limits 

 of the western ice and its behaviour in regard to the invading ice- 

 flow from the north-east were now made clear ; and the detailed 

 study of the physiographical features carved out by the ice-dammed 

 drainage enabled us to visualize the conditions during all stages 

 •subsequent to the maximum glaciation. 



He asked whether the researches of the Author had led him to 

 any conclusion as to the unsatisfactory 'upper boulder-clay', which 

 in this area, as in others, presented many problems in its composi- 

 tion and sporadic mode of occurrence. Had any deposits indicative 

 •of ' interglacial ' conditions been discovered in the area examined ? 



The Author replied that he regarded the presence of boulder- 

 clay above the current-bedded sands and gravels as evidence of 

 periodic re-advances of the ice during the period of retreat, and 

 there was no reason to suppose that the deposits, although similarly 

 arranged, were contemporaneous in different parts of the area. 



With regard to the question of interglacial periods, the Author 

 knew of only one deposit in the district under consideration which 



