120 DARWINISM STATED BY DARWIN HIMSELF. 



Origin of The identity of many plants and animals. 



Species, on mountain-summits, separated from each 

 ^*^^ ■ other by hundreds of miles of lowlands, where 

 Alpine species could not possibly exist, is one of the most 

 striking cases known of the same species living at distant 

 points, without the apparent possibility of their having 

 migrated from one point to the other. It is indeed a 

 remarkable fact to see so many plants of the same species 

 living on the snowy regions of the Alps or Pyrenees, and 

 in the extreme northern parts of Europe ; but it is far 

 more remarkable that the plants on the White Mountains, 

 in the United States of America, are all the same with 

 those of Labrador, and nearly all the same, as we hear 

 from Asa Gray, with those on the loftiest mountains of 

 Europe. Even as long ago as 1747 such facts led Gmelin 

 to conclude that the same species must have been inde- 

 pendently created at many distinct points ; and we might 

 have remained in this same belief, had not Agassiz and 

 others called vivid attention to the Glacial period, which, 

 as we shall immediately see, afEords a simple explanation 

 of these facts. We have evidence of almost every con- 

 ceivable kind, organic and inorganic, that, within a very 

 recent geological period. Central Europe and North Amer- 

 ica suffered under an Arctic climate. The ruins of a 

 house burned by fire do not tell their tale more plainly 

 than do the mountains of Scotland and Wales, with their 

 scored flanks, polished surfaces, and perched bowlders, 

 of the icy streams with which their valleys were lately 

 filled. So greatly has the climate of Europe changed, 

 that in Northern Italy gigantic moraines, left by 

 old glaciers, are now clothed by the vine and maize. 

 Throughout a large part of the United States erratic 

 bowlders and scored rocks plainly reveal a former cold 

 period. 



