336 THE TUNDRAS AND STEPPES OF PREHISTORIC EUROPE. 



which the lemmings and their arctic congeners had formerly prevailed. 

 Throughout both tundra and steppe epochs Palaeolithic man was an 

 occupant of middle Europe. To the steppe epoch succeeded a forest 

 epoch, with its characteristic fauna, by which time Palaeolithic man 

 had vanished, his place being taken by the so-called Neolithic race, or 

 races, for there were several of these. 



We must now ask what relation the tundra and steppes deposits 

 bear to other well-known superficial accumulations of Europe. To 

 what particular stage of the geological history of our continent do 

 they belong 1 ? When we remember that an arctic-alpine flora formerly 

 flourished on the low grounds of central Europe, it seems extremely 

 probable that the tundra epoch must fall within the glacial period. 

 But the glacial period embraced a complex series of geographical and 

 climatic changes, and it is necessary, therefore, to come somewhat closer 

 to the question. Among the most conspicuous deposits of the Ice age 

 are moraines of all kinds and fluvio -glacial gravels, while the loss, as 

 we have seen, is the most prominent accumulation of the tundra and 

 steppe epochs. How, then, does the latter behave with regard to the 

 typical glacial and fluvio glacial formations'? Is it older or younger 

 than these, or are the two sets of accumulations contemporaneous 1 ? 

 The answer we get to that question is, at the first blush, disconcerting, 

 for we learn that it is each in turn — sometimes underlying, sometimes 

 overlying, and in other places occurring intercalated among glacial 

 deposits. This only means, however, that loss appears to have been 

 formed during different stages of the Ice age. It will be remembered 

 that while we discussed the wind-blown character of the loss, we left 

 untouched the question of the origin of its materials. Whence were 

 those materials derived which the wind worked over, and largely 

 rearranged, and redistributed in the low grounds of central Europe? 

 To answer this question we must examine more closely the relation 

 borne by the loss to the fluvio-glacial deposits and morainic accumula- 

 tions. We note, in the first place, that in its horizontal distribution it 

 follows closely that of the valley gravels of glacial times. Where the 

 latter are well developed, the loss appears in full force; where they are 

 wanting there is a like absence of loss. In all the valleys leading down 

 from the Alps to the low grounds of middle Europe the loss puts in a 

 prominent appearance. It obviously bears a close relation to the main 

 lines of drainage, and may be said to be confined to valleys that head 

 in formerly glaciated areas. So, again, in north Germany and southern 

 Eussia it spreads over all the low-lying tracts that lay in front of the 

 vast mers de glace of glacial times. These facts alone, taken in con- 

 nection with the occasional well-stratified character of the loss, the 

 intercalation in it now and again of beds of sand, and the presence 

 ever and anon of fresh-water shells, seem strongly suggestive of a 

 fluviatile origin. And that such was really the origin of the materials 

 of the loss will appear clear enough when we consider the conditions 

 that obtained during a glacial epoch. (See Map A.) 



