30 Smithsonian Exploration in Alaska in 1904 



The sequence of events accompanying the period of elevation and 

 drainage cannot be traced in detail with the facts at hand. They 

 are mentioned here to show there is no necessity for calling in " un- 

 usual accumulations of snow throughout successive years " to ac- 

 count for any of the phenomena under consideration. 



6. elevation and deformation at close of the pleistocene 



It has already been stated that the Pleistocene silts of x\laska 

 are thrown up into broad open folds. These undulations appear 

 best developed where there are the largest areas of silts or through- 

 out the basin areas of the former lakes. The deformation appears 

 to have developed during the period of elevation that marked the 

 close of the period of Pleistocene deposition. This folding was 

 gentle and formed comparatively small shallow lake and pond 

 areas over the drained bottoms of the former extensive lakes. 



7. PROBABLE change OF CLIMATE 



Accompanying this elevation was a change from comparatively 

 mild, temperate conditions, which there is every reason to say ex- 

 isted — for the fauna and flora as far as known demand moderately 

 temperate conditions — to the climate that prevails in these regions 

 today. 



As a better idea of the situation may be presented by quoting 

 from one who has given considerable attention to the subject the 

 following is appended from Sir Henry Howorth "' in an article 

 entitled " The Mammoth Age was Contemporary with the Age of 

 Great Glaciers; " he says: " It is a remarkable fact that if we limit 

 ourselves to the plains of northern Siberia, there is no evidence 

 that a period of severe cold other than that now existing has 

 marked the climate of Siberia since the Mammoth was extinguished. 

 The existence of carcasses in their flesh point to the age they rep- 

 resent having been the last one, the climate having become more 

 and more severe since the Mammoth age. This means, if evidence 

 is to go for anything, that the Mammoth age in Siberia and north- 

 east Europe, which was its last epoch, was contemporary with the 

 Great Glaciers." He quotes Geikie as saying "the IMammoth and 

 the Woolly Rhinoceros may have survived in northern Asia down 

 to a comparatively recent date " "^ and continues : " I cannot see how 

 the conclusion can be avoided, in fact, that in Siberia the ?\Iammoth 



"' Geol. Mag., Lond., 1894, pp. 161-167. 

 "^ The Great Ice Age, 3d ed., pp. 706-707. 



