Septembeb 16, 1910] 



SCIENCE 



357 



masses of rock.'" Both actions may be pos- 

 sible iu a mountain region, but it is very 

 diificult to understand how they covild oc- 

 cur in a lowland or plain. Besides this we 

 can only account for some singular aber- 

 rations of boulders, such as Shap granite 

 well above Grosmont in Eskdale, or the 

 Scandinavian rhomb-porphyry above Lock- 

 wood,'^' 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 cer- 

 tainly water-worn. But if preglacial, the 

 supply would be quickly exhausted, so that 

 they would usually be confined to the lo'^/er 

 part of the clay. As it is, though peihaps 

 they run larger here, they abound through- 

 out. The so-called moraines near York 

 (supposed to have been left by a glacier 

 retreating up that vale), those in the neigh- 

 borhood of Flamborough Head and of 

 Sheringham (regarded as relics of the 

 North Sea ice-sheet) do not, in my opinion, 

 show any important difference in outline 

 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 sup- 



'° That this has occurred at Cromer is a very 

 dubious hypothesis (see Geol. Hag., 1905, pp. 397, . 

 524). The curious relations of the drift and chalk 

 in the islands of ilOen 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. 



°^ About halfway across England and 810 feet 

 above sca-level. P. F. Kendall, Quart. Journ. 

 Geol. Soc, LVIII., 1902, p. 498. 



plied abundant sand, and the older inter- 

 glacial gravels quantities of pebbles; yet 

 the differences between the morainie ma- 

 terials 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 tres- 

 passing upon the coast of England, but also 

 radiating southward to overwhelm Den- 

 mark and Holland, to invade northern Ger- 

 many and Poland, to obliterate Hanover, 

 Berlin and Warsaw, and to stop but little 

 short of Dresden and Cracow, while bury- 

 ins^ Russia on the east to within no great 

 distance of the Volga and on the south to 

 the neighborhood of Kief. Their presence; 

 however, so far as I can ascertain, is in- 

 ferred from evidenee^^ very similar to that 

 which we have discussed in the British low- 

 lands. That Scandinavia was at one time 

 abnost wholly buried beneath snow and ice 

 is indubitable; it is equally so that at the 

 outset the land stood above its present level, 

 and that during the later stages of the 

 glacial epoch parts, at any rate of southern 

 Norway, had sunk doAvn to a maximum 

 depth of SOO feet. In Germany, however, 

 erratics are scattered over its. plain and 

 stranded on the slopes of the Harz and 

 Riesengebirge up to about 1,400 feet above 

 sea-level. The glacial drifts of the low- 

 lands sometimes contain dislodged masses 

 of neighboring rocks like those at Cromer, 

 and we read of other indications of ice 

 action. I must, however, observe that since 

 the glacial deposits of Moen, Warnemiinde 

 and Riigen often present not only close 

 resemblances to those of our eastern coun- 

 ties but also very similar difficulties, it is 

 not permissible to quote the one in support 



^A valuable summary of it is given in "The 

 Great Ice Age," J. Geikie, ch. XXIX., XXX., 1894. 



