346 HISTORY OF THE EUROPEAN FAUNA. 



authors. To quote the words of this distinguished 

 botanist (p. 576): "Is it credible that in the short 

 interval since the close of the Glacial period hundreds 

 of very distinct species and several genera have been 

 developed in the Alps, and what is no less hard to 

 conceive that several of these non-Arctic species 

 and genera should still more recently have been 

 distributed at wide intervals throughout a discon- 

 tinuous chain some 1500 miles in length, from the 

 Pyrenees to the Eastern Carpathians? Nor would 

 the difficulties cease there. You would have left un- 

 explained the fact that many of the non- Arctic types 

 which are present in the Alps are represented in the 

 mountains of distant regions, not by the same, 

 but by allied species, which must have descended 

 from a common ancestor; that one species of 

 Wulfenia> for example, inhabits one small corner of 

 the Alps, that another is found in Northern Syria, 

 while a third allied species has its home in the 

 Himalaya." Mr. Ball is of opinion (p. 584) that 

 the effects of the Glacial period have been greatly 

 overrated. " Even during the period of maximum 

 cold the highest ridges of the Alps were not com- 

 pletely covered with snow and ice; for we still see 

 by the appearance of the surface, the limit above 

 which the ancient ice did not reach, and in the middle 

 zone the slopes that rose above the ancient glaciers 

 had a summer climate not very different from that 

 which now prevails. In my opinion the effect of the 

 Glacial period on the growth of plants in the Alps 



