RESUME AND GENERAL DISCUSSION. 387 



passage-way was certainly opened through the present Gnlf of St. Lawrence, 

 and perhaps also from Hudson's Bay, and through this icebergs may naturally 

 have been carried in great numbers toward more southern regions. 



Section V. — Resume and General Discussion. 



The facts brought forward in the second chapter of the present volume, 

 and the discussion which followed in the succeeding one, were passed over in 

 a rapid review at the close of that portion of the work which is devoted to 

 the siibject of desiccation.* It will now be proper to do the same for the 

 present chapter, in which a large body of material has been laid before the 

 reader, and in many cases with accompanying comments. Some repetition 

 will be unavoidable; but it is thought that such a resume as is here proposed 

 is desirable, even if it adds somewhat to the size of the volume, especially as 

 it will furnish an opportunity for enlarging on some points of special impor- 

 tance, and of introducing a few considerations which have not found a place 

 in the preceding pages. 



We have already seen most clearly that it is possible to lay aside all idea 

 of explaining the phenomena of the so-called Glacial epoch, by referring 

 them to the extension of a general or Polar ice-cap over the land of the 

 northern hemisphere. The fact that this idea, so popular a few years ago 

 among glacial geologists, may now be rejected without hesitation, is a proof 

 that some progress has been made in this department of climatic geology. 

 As already suggested, the explorations of the California Survey fifteen years 

 ago showed so clearly the real character of the glaciation of the Cordilleras, 

 and how unlike it was to that of Northeastern North America, that the idea 

 of a general ice-cap on this continent had at once to be abandoned, while the 

 more recent scientific explorations of Northern Asia have proved the same 

 thing to be true for the Old World. 



The entire body of facts presented brings out most clearly the true con- 

 dition of things, namely, that the Glacial epoch was a local phenomenon, 

 during the occurrence of which much the larger part of the land-masses of 

 the globe remained climatologically entirely unaffected. We have seen how 

 at the present time glaciers are limited to mountain ranges, and to such as 

 are favorably situated with respect to prevailing moisture-bearing winds. 

 We have also had abundant exemplification of the fact that high mountain 



* See ante, p. 264. 



