186 DK. C. T. TEECHMAXX OX IXTEKGLACIAL [vol. lxxV, 



I leave out of discussion the question of the deep area or fosse 

 off the Norwegian coast, because it does not present any difficulty 

 to my mind. It was probably filled with ice at an early stage, or, 

 if not, it is now known that round the fringes of the Antarctic 

 Continent the ice-cap floats in some places on deep water. One 

 of the main points of evidence in support of the view of the 

 gradual advance of the Scandinavian ice-sheet across the North- 

 Sea area is the distribution of the different varieties of Scandi- 

 navian erratics along the east coast of England. 



The Scandinavian Drift in Durham contains only Norwegian 

 boulders, no Swedish erratics having been traced in it. 



According to the work of Dr. Y. Milthers on the Continent, in 

 Holland the limit of the Drift that contains only Norwegian 

 boulders lies south of the mouths of the Rhine and Maas. extend- 

 ing southwards and eastwards to Antwerp, and the island of Over 

 Elakke. Milthers colours this area in a map l so as to indicate 

 that only Norwegian erratics occur, and in the same map he pro- 

 visionally indicates by the same colour that the whole of the east 

 coast of England, from the Tees southwards to Norwich, including 

 the eastern part of Yorkshire, Lincolnshire, and Norfolk, similarly 

 contains only Norwegian erratics. This shows how small has been 

 the amount of detailed glaciological work in this country com- 

 pared with that accomplished on the Continent. Milthers is not 

 correct in supposing these to be the limits in England of the 

 Scandinavian erratics, for they have been traced over a much wider 

 area in the south-eastern counties north of London than he indi- 

 cates on his map. Neither is he correct in supposing that only 

 Norwegian rocks occur in England, because it is Avell known that 

 Swedish and Baltic rocks occur in Holderness, where I have picked 

 up Swedish quartz-porphyries and Bapakivi Granites. I cannot, 

 however, say that I have ever found the last-mentioned in situ 

 in the undisturbed Basement-Clay, but I presume that such an 

 occurrence has been recorded. 



I do not know where in Yorkshire these Swedish rocks begin to 

 occur, as I have never had the opportunity of examining the 

 Yorkshire Drifts so closely as I have those farther north, but 

 I presume that they begin to occur south of Flamborough Head. 

 North of that point only Norwegian rocks will (I think) be found; 

 but in Holderness, if an enumeration could be made of all the 

 ScandinaA'ian stones occurring in situ in the Drift, the Norwegian 

 erratics would probably be feund to number about 50 to 80 

 per cent, of the total Scandinavian erratics : the remainder being 

 Swedish. This proportion, according to Milthers, characterizes the 

 Drifts of Schleswig-Holstein and those about Hamburg. 



These considerations, together with the occurrence of loess and 

 of the various materials carried in advance of the ice-sheet, tend to 

 confirm the general agreement of the Scandinavian Drift of 

 England with that of the rest of Northern Europe. 



1 ' Scandinavian Indicator-Boulders in the Quaternary Deposits ' Dan- 

 marks Geol. Fndersog. ser. 2, no. 23 (1909) pi. ii. 



