REVIEWS. 741 



Specific bits of evidence, or even whole lines of evidence, which are 

 cited in support of separate epochs, might be interpreted in some 

 other way. But in dealing with such questions we have always to 

 remember that several lines of evidence, no one of which is absolutely 

 conclusive, may together be so strong as to carry conviction. The 

 question is not whether this or that bit or line of evidence might be 

 explained in some other way than by the theory of distinct glacial 

 epochs, but whether, as a matter of fact, the aggregate of evidence com- 

 pels the adoption of this theory. The question is not what might have 

 been, but what was. 



According to Professor Geikie the sequence of events during the 

 prolonged glacial period is as follows : (1) A glacial epoch, preceded 

 by a period of increasing cold. At this time ice filled the basin of 

 the Baltic. The Alpine lands were swathed in snow and ice, and 

 great glaciers came out from the mountains, making moraines, on the 

 low ground at their bases. The mountain regions of Britain were 

 probably ice-clad, though of this there is no direct evidence. In France 

 there were glaciers from the volcanic cones of Auvergne and Cantal, 

 which descended so as to deploy upon the plateaus. (2) Then fol- 

 lowed the first interglacial epoch. The southern part of the North 

 Sea became land, and a temperate flora, comparable to that of England 

 today, covered corresponding latitudes. A luxuriant deciduous flora 

 occupied the valleys of the Alps, and flourished at heights which it no 

 longer reaches. (3) The first interglacial epoch was succeeded by a 

 second glacial epoch. During this time the northern men de glace 

 reached its greatest extent. At the same time, the Alpine glaciers 

 reached their greatest extension, while in the other mountains of Europe 

 snow fields and glaciers came into existence. (4) The dissolution of 

 this ice sheet was followed by a second interglacial epoch. The cli- 

 mate of Northern and Central Europe again became temperate, a tem- 

 perate flora and fauna finally replacing the arctic forms which first 

 tenanted the land after the ice disappeared. The plants which occu- 

 pied Germany and the central plains of Russia indicate a less extreme 

 climate than is now experienced in these regions. Later, the climate 

 became more rigorous. The amount of erosion accomplished during 

 this second interglacial interval was such as to testify to its great dura- 

 tion. (5) A less extensive, but still great ice sheet overwhelmed a 

 large part of the British Islands, and spread itself widely upon the 

 continent. As in the preceding epoch the Scandinavian and British 



