694 ANlSrUAL REPORT SMITHSONIAN INSTITUTION, 19 2 8 



decide to which of these isolated prehistoric finds should be at- 

 tributed. Most Quaternary geologists, however, seem to agree that 

 at least two separate glaciations must be regarded as well established, 

 those known respectively as the " great " and the " last glaciation." 

 Of these the last is incomparably the best known, since it is the only 

 one of which the deposits are accessible for close investigation. The 

 deposits of the great glaciation are nowadays preserved almost no- 

 where but outside the limits of the last glaciation. Deposits from the 

 older stages of the glaciations are often concealed or totally destroyed 

 by the later movements of the land ice. It is not, therefore, surpris- 

 ing that geologists hold very different views with respect to the num- 

 ber as well as the extent of the oscillations of the ice, and also to the 

 question of how many of these may be ranked as independent glacia- 

 tions. The difficulties in the way of solving this important question 

 are very great, but until they are overcome it is too early to attempt 

 to relate the older cultural epochs of the Paleolithic Age with the 

 glacial or interglacial stages. 



The last receding land ice has, however, left to posterity a re- 

 markable and complete autoregistration, covering the whole of the 

 melting epoch. There is here no question of relative computation, 

 but the direct reading and counting of the varves deposited by the 

 water formed every year, as long as the melting epoch lasted. For 

 the late Quaternary epoch, after the maximum of the last glaciation, 

 we have already a very comprehensive series of measurements from 

 a great number of localities, and when the whole has been worked 

 through we shall have an exact time scale for the period which is by 

 far the most important in the evolution of prehistoric cultures. The 

 next stage is to find some region where sediment accumulated during 

 the whole of the Quaternary epoch, in its glacial as well as post- and 

 interglacial stages. These conditions may be found to prevail in 

 several delta regions which received sediment from .some greater 

 glaciated area throughout the Quaternary period. Such was the 

 relation of the Ganges-Brahmaputra delta to the eastern Himalaya. 

 It would, however, be impracticable to begin with so immense an 

 area before the method had been tried on a smaller one. The Indus 

 delta would, from every point of view, be more suitable. This delta 

 has recorded the sedimentary deposits from the Kashmir area of 

 the northwestern Himalaya, where, in connection with the Geochro- 

 nological Institute, E. Norin has begun to make a comprehensive 

 analysis of the Quaternary deposits, which already seems to give a 

 direct correlation with the Swedish time scale. It might, however, 

 prove still more convenient in the first instance to take up the in- 

 vestigation of a delta more easy of access, such as that of the Po, 

 which might be expected to offer a fairly complete registration of 

 Quaternary deposits from the whole southern slope of the Alps. 



