19G Proceedings of the lioijul Irish Academy. 



long ago pointed out how corry-glaciers might be fed by snow drifted into 

 pre-existing hollows. 



The latest champion of the theory that cirques have originated under 

 ice-streams is E. C. Andrews,' who treats cirques, however, merely as steps 

 occurring in a glaciated valley-floor. He does not seem to have borne in 

 mind the occurrence of cirques, almost as local accidents, cut out here and 

 there on a wall moulded by general denudation. Yet this irregular distribu- 

 tion is a marked feature of the edges of our ancient plateaus and divides. 

 The hollows of Upper and Lower Lough Bray are familiar instances near 

 Dublin. In Spitsbergen, on sea-fronts where stepped valleys are out of the 

 question, and on plateau-edges independent of any possible ice-stream, one 

 may see the cirques in process of development, each resembling a local centre 

 of some corrosive malady. The remarks of E. C. Andrews, that " no observer 

 appears to have seriously considered the possibility, or probability, that the 

 cirque has been formed by activities now practically inoperative,"" is true 

 enough. In the face of the cirques that may be studied in glaciated regions 

 in all stages of growth, it would be impossible to accept such a view seriously. 

 It would be difficult, for instance, to regard those near the foot of the 

 Matterhorn^ as due to a past stage of Alpine glaciation. 



In the plateaus of Spitsbergen some of the alcoves have originated on such 

 steep slopes that they cannot have nourished actual glaciers. The frost has 

 worked back the cirque-head, and snow-slides have carried away the detritus. 

 The climber may sink in summer up to his knees in crumbled rock, sludgy 

 with water, formed along the margin of the snow that gathers in their heads. 

 But here and there, on gentler slopes, we may note the origin of cirques of 

 more typical and basin-like form. Small or large, they are still developing as 

 notches on the plateau-edge, and, by their recession, the plateau becomes 

 ultimately cut up into aretes. The protective snow-cap, so well emphasized 

 by Garwood and by Hobbs, then ceases to be a possibility, unless precipitation 

 becomes greatly increased. Such snow as now falls slips into the cirques, and 

 generates localized glacial action. 



The progress of the " cirque- chsease," attacking a plateau from which the 

 snow now recedes in summer, may be well seen in the interior of Dickson Land, 

 as viewed from the heights above Cape Wijk (PI. XL, fig. 6). In the view 

 selected, numerous stream-grooves, formed by rills from melting snow, seam 



' " An Excursion to the Voseraite, or Studies in the Formation of Alpine Cirques," Proc. Boy. 

 Soc. New South Wales, vol. xliv (1910), pp. 302 and 305. 



- Op. cit., p. 265. 



'One of these is figured, from a photograph hy W. F. Donkin, in G. Cole, "Open -Air Studies 

 in Geology" (1896), Plate II. 



