Geographical Distribution. 209 



one time the species occupied the whole of the range 

 in question, but afterwards became broken up as 

 geographical, climatic, or other changes rendered 

 parts of the area unfit for the species to inhabit. 

 Thus, for instance, it is easy to understand that 

 during the last cold epoch the mountain-hare would 

 have had a continuous range ; but that as the Arctic 

 climate gradually receded to polar regions, the species 

 would be able to survive in southern latitudes only 

 on mountain ranges, and thus would become broken 

 up into many discontinuous patches, corresponding 

 with these ranges. In the same way we can explain 

 the occurrence of Arctic vegetation on the Alps and 

 Pyrenees namely, as left behind by the retreat of 

 the Arctic climate at the close of the glacial period. 



But now, on the other hand, the theory of special 

 creation cannot so well afford to render this obvious 

 explanation of discontinuity. In the case of the 

 Arctic flora of the Alps, for instance, although it is 

 true that much of this vegetation is of an Arctic type, 

 it is not true that the species are all identical with 

 those which occur in the Arctic regions. Therefore 

 the theory of special creation would here have to 

 assume that, although the now common species were 

 left behind on the Alps by the retreat of glaciation 

 northwards, the peculiar Alpine species were after- 

 wards created separately upon the Alps, and yet 

 created with such close affinities to the pre-existing 

 species as to be included with them under the same 

 genera. Looking to the absurdity of this supposition, 

 as well as of others which I need not wait to mention, 

 certain advocates of special creation have sought to 

 take refuge in another hypothesis namely, that 



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