( 221 ) 



XII. — Ice-Erosion in the Cuillin Hills, Skye. By Alfred Harker, M.A., F.G.S., 

 Fellow of St John's College, Cambridge; H.M. Geological Survey of Scotland. 

 Communicated by John Horne, F.R.S. (With a Map.) 



(Read 20th May 1901.) 



I. General Account of the Glaciation 



of Central Skye 221 



(i.) Introduction 221 



(ii.) Independent Ice-Cap of the Skye 



Mountains 222 



(iii.) Movement of Ice during the Great 



Glaciation 225 



II. Physical Features of the Cuillin Hills as 



a typical district of Ice-Erosion . . 227 

 (iv.) General Considerations . . . 227 

 (v.) Independence of Physical Features and 



Geological Structure . . . 230 



page. 



(vi.) Forms of the Valleys, and Relation of 



Tributaries to Principal Streams 

 (vii.) Cirques : Character of the Ridges 

 (viii.) Longitudinal Profile of Valleys : Lake- 

 Basins ...... 



(ix.) Asymmetric Element in the Surface- 

 Relief 



III. The Glacial Accumulations and 

 their testimony to ice- and frost- 



Erosion 



(x.) Drift Deposits . . . . .242 

 (xi.) Later Glaciers and Frost-Erosion . . 248 



231 

 234 



237 



240 



242 



I. General Account of the Glaciation of Central Skye. 



(i.) Introduction. 



Since the publication in 1846 of a brief but valuable memoir by J. D. Forbes, in 

 which that author drew attention to " the traces of ancient glaciers " in the Cuillin 

 Hills, that district has remained almost unnoticed by glacial geologists for half a 

 century.* This neglect is doubtless attributable chiefly to the difficulty of access to 

 the mountains, a consequence of their peculiar configuration, which in turn is closely 

 bound up with the glacial history of the district. The present contribution is the 

 outcome of observations made during the years 1895-1900 in mapping the central 

 part of Skye for the Geological Survey of Scotland.! In traversing the mountains 

 day after day throughout several successive seasons, the writer has been struck 

 especially by the impressive evidence which they present of glacial erosion as the 

 dominant factor in their sculpture, and to enforce this is the chief object of the present 

 communication. 



* J. D. Forbes, " Notes on the Topography and Geology of the Cuchullin Hills in Skye, and on the Traces of 

 Ancient Glaciers which they Present," Edin. New Phil. Joum., vol. xl. pp. 76-99, pi. iv., v., 1846. Among scattered 

 notices of later date, see A. Geikie, " On the Phenomena of the Glacial Drift of Scotland," Trans. Geol. Soc. Glasg. y 

 vol. i. part ii., 1863 ; and J. Geikie, The Great Ice Age ; also for the adjacent Red Hills, T. G. Bonney, "On a 

 Circme in the Syenite Hills of Skye," Geol. Mag. 1871, pp. 535-540. 



+ Some of these observations have been briefly recorded in the Summary of Progress for 1897 and 1898. See 

 also Harker, " Glaciated Valleys in the Cuillins, Skye," Geol. Mag. 1899, pp. 196-199. In the following pages the 

 subject is developed more fully than would be convenient in an official publication. 



VOL. XL. PART II. (NO. 12). 2 L 



