i9i8. HiNCH. — 71ie Irish Sea Glacier. 57 



Killakec valley, at 1,270 feet, shells and erratics have been 

 found, and this locality is believed to be the highest eleva- 

 tion at which they have been found in Ireland.^ 



Two reports are available from the valley of the Litfey, 

 where W. B. Wright and the writer found shell-fragments 

 in gravels at Astagob, east of Lucan, and in Lucan demesne, 

 between Lucan and Leixlip. These records of shell- 

 fragments from the valley of the Liffey are the most 

 westerly obtained up to the present. 



In County Wicklow a number of localities may be cited 

 as having yielded evidence of the passage of the glacier 

 across the district. Last year W. H. Hinde, the engineer- 

 in-charge of the construction of the new Bray Head tunnel, 

 discovered shells and erratics in the boulder-clay and sand 

 through which the timnel was being cut. As the shells were 

 found over 1,000 feet from the entrance and nearly 100 feet 

 below the surface, this discovery is most interesting. A 

 number of arctic shells and northern erratics have been 

 obtained by W. H. Hinde and the writer up to the present, 

 and further investigations are to be continued during the 

 present year. South of Bray Head, towards Greystones, 

 shell fragments and erratics have been found by W. B. 

 Bruce and the writer in a number of localities, while inland, 

 on the eastern slopes of the Great Sugarloaf, the gravel 

 deposits have yielded satisfactory results. 



It is now necessary to turn from the western shore of 

 the Irish Sea basin in order to follow the course pursued 

 by the Irish Sea Glacier after it had crossed the Isle of Man. 

 The evidence shows that the ice-sheet, having reached the 

 northern coast of Wales, divided into two great lobes in 

 order to avoid the Snowdon range, over which it was not 

 powerful enough to pass, as in the case of the Isle of Man. 

 The eastern lobe swept inland over the low-lying Cheshire 

 plain as far south as Shrewsbury in Shropshire, and from 

 many localities far inland from the sea arctic shells and 

 erratics have been obtained. The western lobe of the 

 ice-sheet turned west and south across Caernarvon and 



^ J. de W. Hinch, " The occurrence of high-level shelly-drift, in the 

 Killakee Valley, Co. Dubhn," Irish Naturalist, vol. xvii., pp. 99-100 

 (1908). 



