4i8 Notes and Comments. 



the north German lowland. It is possible that the rather fresh 

 deposits of the Scandinavian ice field, that are buried beneath 

 the morainic drift, will correlate with the middle drift of north 

 Germany. They mark an extension of Scandinavian ice that 

 seems greater than would be consistent with the extent of the 

 upper drift in Germany, but which would fall in naturally as 

 a continuation of the middle drift border from north eastern 

 Holland across the North Sea basin.' 



BRITISH ICE SHEETS. 



' The district ice sheets and mountain valley glaciers of 

 Great Britain are thought by Geikie to be so widely separated 

 from the glaciation that produced the morainic drift just dis- 

 cussed, as to be referable to distinct stages of glaciation named 

 the Lower Turbarian and Upper Turbarian. The evidence 

 seems clear that the ice sheets of the north part of Great Brtain 

 were subject to increase and decrease in response to climatic 

 variations, and that there have been times of low elevation 

 and incursion of the sea that correspond somewhat to enlarged 

 glaciation. This evidence is of great value in bringing out the 

 later history of the ice sheets, and is of similar import to evi- 

 dence found in Scandinavia in showing there has not been a 

 steady amelioration of climate, since the culmination of the 

 last stage of glaciation.' 



CONCLUSIONS. 



' The writer is not disposed to minimize these results in 

 the least. The dissent from Geikie 's interpretation is merely 

 a matter of the proper terms to apply to such climatic changes. 

 It has been shown in the course of the present discussion that 

 there are very pronounced differences in amount of weathering 

 and erosion, and in general aspect as to age in deposits that 

 have been referred to different glacial stages. The differences 

 are so great as to seem to require more time in each inter- 

 glacial stage than has elapsed since the outer portion of the 

 drift of the fourth glacial stage became exposed to weathering 

 and erosion. These expanded glacial conditions which Geikie 

 has ranked as stages are so much briefer than any of the pre- 

 vious glacial stages that it seems more fitting to rank them 

 as stadia of the waning portion of the fourth stage of glaciation, 

 and to class the breaks between them as interstadial rather 

 than interglacial, for it is not known that the ice completely 

 disappeared between the times of expanded glaciation.' 



Naturalist, 



