26 president's address. 



its operations. It is supposed in one place to have glided gently 

 over its bed, in another to have gripped and torn out huge masses of 

 rock. 1 Both actions may be possible in a mountain region, but it is 

 very difficult to understand how they could occur in a lowland or plain. 

 Besides this we can only account for some singular aberrations of 

 boulders, such as Shap granite well above Grosmont in Eskdale, or the 

 Scandinavian rhomb-porphyry above Lockwood, 2 near Huddersfield, by 

 assuming a flexibility in the lobes of an ice-sheet which it is hard to 

 match at the present time. Again, the boulder clay of the Eastern 

 Counties is crowded, as we have described, with pebbles of chalk, which 

 generally are not of local origin, but have come from north of the Wash. 

 Whether from the bed of a river or from a sea-beach, they are certainly 

 water-worn. But if preglacial. the supply would be quickly exhausted, 

 so that they would usually be confined to the lower part of the clay. 

 As it is, though perhaps they run larger here, they abound throughout. 

 The so-called moraines near York (supposed to have been left by a 

 glacier retreating up that vale), those in the neighbourhood of Flam- 

 borough Head and of Sheringham (regarded as relics of the North Sea 

 ice-sheet) do not, in my opinion, show any important difference in out- 

 line from ordinary hills of sands and gravels, and their materials are 

 wholly unlike those of any indubitable moraines that I have either seen 

 or studied in photographs. It may be said that the British glaciers 

 passed over very different rocks from the Alpine ; but the Swiss molasse 

 ought to have supplied abundant sand, and the older interglacial gravels 

 quantities of pebbles ; yet the differences between the morainic materials 

 on the flank of the Jura or near the town of Geneva and those close to 

 the foot of the Alps are varietal rather than specific. 



Some authorities, however, attribute such magnitude to the ice- 

 sheets radiating from Scandinavia that they depict them, at the time 

 of maximum extension, as not only traversing the North Sea bed and 

 trespassing upon the coast of England, but also radiating southward to 

 overwhelm Denmark and Holland, to invade Northern Germany and 

 Poland, to obliterate Hanover, Berlin, and Warsaw, and to stop but 

 little short of Dresden and Cracow, while burying Bussia on the east to 

 within no great distance of the Volga and on the south to the neighbour- 

 hood of Kief. Their presence, however, so far as I can ascertain, is in- 

 ferred from evidence * very similar to that which we have discussed in the 



1 That this has occurred at Cromer is a very dubious hypothesis (see Oeol. Mag., 

 1905, pp. 397, 524). The curious relations of the drift and chalk in the islands of 

 Moen and Riigen are sometimes supposed to prove the same action. Knowing both 

 well, I have no hesitation in saying that the chalk there is, 'as a rule, as much in situ 

 as it is in the Isle of Wight. 



2 About half-way across England and 810 feet above sea-level. P. F. Kendall, 

 Quart. Journ. Oeol. Soc, Iviii. (1902), p. 498. 



3 A valuable summary of it is given in The Great Ice Age, J. Geikie. ch. xxix., xxx. 

 (1894). 



