lxxii PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [vol. lxxvi, 



shown how the snout of a rapidly retreating glacier, aground on 

 an island in one of the branches of Ice Fiord, had become detached 

 from its pai'ent-mass and left behind in the retreat. It Avas being 

 dissected by melting ; and we found that the surface of the ice 

 and the ground around it were blanketed with a thick mass of 

 shelly clay remarkably similar to some of our English lowland 

 boulder-clays. 1 The ' terminal moraine ' in this case was a mud- 

 belt, rather lumpy at the time of our visit, but likely soon to be 

 reduced to a smooth plane by exposure to the weather. The con- 

 ditions here on a small scale were similar to those which must have 

 ruled on a large scale at the receding borders of our lowland ice- 

 sheets ; and, with this instance in mind, it seems reasonable to 

 regard the broad thick belts of boulder-clay of our eastern and 

 midland counties as a modified form of 'terminal moraine. 1 their 

 deposition in such masses being a mark of the terminal en feeble - 

 ment of the invading ice. 



Another point of importance bearing upon the characteristics of 

 the Glacial deposits, whicb is gradually emerging from the study 

 of existing glaciers and ice-fields, is the cumulative evidence that 

 ice-movement is rarely, if ever, regular, but proceeds b} r the alter- 

 nation of short periods of quick advance with longer intervals of 

 stagnation or relative quiescence. This condition has been found 

 now in every region where existing glaciers have been brought 

 under observation. It is perhaps best known in respect of certain 

 glaciers of Alaska, Spitsbergen, and the Himalaya 3 ; but has been 



1 The circumstances were described to this Society on December 10th, 

 1910, by Sir Aubrey Strahan, in a lecture with lantern-illustrations. They 

 are dealt with, also, in a paper ' On the Shelly Moraine of the Sef strom Glacier 

 & other Spitsbergen Phenomena illustrative of British Glacial Conditions ' 

 by G. W. Lamplugh, Proc. Yorks. Geol. Soc. vol. xvii, pt. 3 (1911) pp. 216-41 ; 

 and in ' Glacial Features in Spitsbergen in relation to Irish Geology ' by Prof. 

 G. A. J. Cole, Proc. Boy. Irish Acad. vol. xxix (1911) pp. 191-208. A previous 

 account of the glaciers and their recent changes was given by Prof. G. J. 

 De Geer in a ' Guide ' prepared for the Congress Excursion. 



2 The literature is too copious for full references, but I may cite the 

 following as examples: — Alaska — 'The Yakutat Bay Eegion ' by R. S. Tarr 

 & B. S. Butler, U.S. Geol. Surv. Profess. Paper 64 (1909), and ' The Earth- 

 quakes at Yakutat Bay in September, 1899 ' by R. S. Tarr & L. Martin, ibid. 69 

 (1912); Spitsbergen — ' Guide de l'Excursionau Spitsberg' by G.J. DeGeer> 

 Xl&me Congres G<5ol. Internat. Stockholm (1910) ; Himalaya—' Glacier 

 Exploration in the Eastern Karakoram,' with appendix, 'Notes on the 

 'glaciers of the Upper Shyok Valley ' by T. G. Longstaff, Geogr. Journ. 

 vol. xxxv (1910) pp. 622-53 ; also further discussion in papers by Sven 

 Hsdin and W. H. Workman, ibid. vol. xxxvi (1910) pp. 184^94, and 194-96. 





