TKAXSACTIONS OF SECTION C. 555 



The limits readied by the inland ice durinpr its greatest extension are becoming 

 more and more clearly defined, although its southern margin will probably never 

 be 80 accurately determined as that of the latest epoch of general glaciation. The 

 reasons for this are obvious. AVhen the inland ice flowed south to the Ilarz and 

 the hills of Saxony it formed no great terminal moraines. Doubtless many erratics 

 and much rock-rubbish were showered upon the surface of the ice from the higher 

 mountains of Scandinavia, but owing to the fanning-out of the ice on its southward 

 march such superficial debris was necessarily spread over a constantly widening 

 area. It may well be doubted, therefore, whether it ever reached the terminal 

 front of the ice-sheet in sufficient bulk to form conspicuous moraines. It seems 

 most probable that the terminal moraines of the great inland ice would consist of 

 low banks of boulder-clay and aqueous materials — the latter, perhaps, strongly 

 predominating, and containing here and there larger and smaller angular erratics 

 which had truvelled on the surface of the ice. However that may be, it is certain 

 that the whole region in question has been considerably modified by subsequent 

 denudation, and to a large extent is now concealed under deposits belonging to 

 later stages of the Pleistocene period. The extreme limits reached by the ice are 

 determined rather by the occasional presence of rock-strite and roc/ies moutimnies, 

 of boulder-clay and northern erratics, than by recognisable terminal moraines. 

 The southern limits reached by the old inland ice appear in this way to have been 

 tolerably well ascertained over a considerable portion of Central Europe. Some 

 years ago I published a small sketch-map ^ showing the extent of surface formerly 

 covered by ice. On this map I did not venture to draw the southern margin of 

 the ice-sheet in Belgium further south than Antwerp, where northern erratics 

 were known to occur ; but the more recent researches of Belgian geologists show 

 that the ice probably flowed south for some little distance beyond Brussels.* 

 Here and there in other parts of the Continent the southern limits reached by the 

 northern drift have also been more accurately determined, but, so far as I know, 

 none of these later observations involves any serious modification of the sketch- 

 map referred to. 



I have now said enough, however, to show that the notion of a general ice- 

 sheet having covered so large a part of Europe, which a few years ago was looked 

 upon as a wild dream, has iDeen amply justified by the labours of those who are so 

 assiduously investigating the peripheral areas of the 'great northern drift.' And 

 perhaps I may be allowed to express my own belief that the drifts of Middle and 

 Southern England, which exhibit the same complexity as the ' lower diluvium ' of 

 the Continent, will eventually be generally acknowledged to have had a similar 

 origin. I have often thought that whilst politically we are happy in having the 

 sea all round us, geologically we should have gained perhaps by its greater distance. 

 At all events we should have been less ready to invoke its assistance to explain 

 every puzzling appearance presented by our glacial accumulations. 



I now pass on to review some of the general results obtained by continental 

 geologists as to the e.xtenl- of area occupied by inland ice during the last great 

 extension of glacier-ice in Europe. It is well known that this latest ice-sheet did 

 not overflow nearly so wide a region as that underneath which the lowest boulder- 

 clay was accumulated. This is shown not only by the geographical distribution of 

 the youngest boulder-clay, but by the direction of rock-striae, the trend of erratics, 

 and the position of well-marked moraines. Gerard de Geer has given a summary* 

 of the general results obtained by himself and his fellow-workers in Sweden and 

 Norway ; and the.se have been supplemented by the labours of Berendt, Geinitz, 

 Hauchecorne, Keilhack, Klockmann, Schroder, Wahnschafli?, and others in Ger- 

 many, and by Sederholm in Finland.' From them we learn that the end-moraines 



' Prehistoric Europe, 1881. 



' See a paper by M. E. Delvaux : Ann. de la Sac. gcol. de Belg., t. xiii., i). 158. 



' Zeitschrift d. deutsch. gcolog. Get., Bd. xxxvii., p. 177. 



* For papers by Berendt and liis a.-^ociatcs see especially the Jahrbuch d. k.j>reust. 

 geol. Landcmnstalt, and the ZciUclir. d. deutsch. geol. Gcs. for the past few years ; 

 Geinitz : Fortch. z. d. Landn- v. Volliskunde, I., 5 ; LeojtoldiiM, xxii., p. 37 ; I. Beitrag 

 z. Geologic Mecklenburgi, 1880, pp. 46, 56. Sederholm : Fennia, I., No. 7. 



