GLA CIAL S UC CESSION IN NOR WA V. 1 29 



interglacial, deuteroglacial, and postglacial periods, all very 

 clearly denoted by these names. 



The proteroglacial period came at last to an end. The ice 

 retired very much ; an interglacial period followed. Of this 

 warmer period we know very few certain traces in Norway. 

 Almost every deposit referable to it has been swept out by the last 

 — the deuteroglacial — ice sheet at least in the parts best studied. 

 At Jaederen we certainly have some layers of gravel and sand 

 between the undermost bottom moraine carrying boulders from 

 the Kristiania territory, and the uppermost one bearing boulders 

 from the mountains close by on the east, but these layers do not 

 contain, as far as known, any fossils giving information about 

 the climate, and it may very probably be that they must be 

 referred to the retiring proteroglacial or the advancing deuter- 

 oglacial ice. 



The part of the proteroglacial country which was not covered 

 by the deuteroglacial ice sheet or sea — and which, therefore, might 

 have retained interglacial deposits — is very poor in loose matter 

 and it has, as yet, not been possible to distinguish any interglacial 

 debris. In the center of the country at Vage, near the highest 

 mountains in Norway, there was some years ago found in river 

 gravel a molar of the mammoth. It may now be said, that this 

 tooth is certainly neither postglacial, protero- nor deutero- 

 glacial, as the tract in these periods was quite ice-covered. There 

 remains the assumption that it is preglacial or interglacial, and as 

 it is not very probable that this molar has remained unmolested 

 through the very long first glaciation by which the whole country 

 was deeply eroded, it is perhaps permissible to take it for inter- 

 glacial. In this case we may conclude that the country in inter- 

 glacial time was covered with forest up to the highest plateaus ; 

 and, therefore, the proteroglacial hiland ice was entirely gone. 



It is, however, more reliable to seek for support by a compari- 

 son with neighboring countries. The peats in parts of Denmark 

 not deuteroglaciated show an arctic flora with Dryas, Salix polaris, 

 herbacea, and reticulata, which followed the great retreating protero- 

 glacial ice sheet, and this was superseded by a vegetation char- 



