274 Canadian Record of Science. 



phenomena attributable to ice action in this period. In 

 considering this question, it must be borne in mind that the 

 greater masses of floatiug ice are produced at the seaward 

 extremities of land glaciers, and that the heavy field-ice of 

 the Arctic regions is not so much a result of the direct freez 

 ing of the surface of the sea as of the accumulation of snow 

 precipitated on the frozen surface. In reasoning on the 

 extent of ice action, and especially of glaciers in the Pleis- 

 tocene age, it is necessary to keep this full in view. Now in 

 the formation of glaciers at present — and it would seem also 

 in any conceivable former state of the earth — it is necessary 

 that extensive evaporation should conspire with great con- 

 densation of water in the solid form. Such conditions exist in 

 mountainous regions sufficiently near to the sea, as in Green- 

 land, Norway, the Alps, and the Himalayas ; but they do not 

 exist in low arctic lands like Siberia or Grinnel-land, nor in 

 inland mountains. It follows that land glaciation has narrow 

 limits, and that we cannot assume the possibility of great 

 confluent or continental glaciers covering the interior of wide 

 tracts of land. No imaginable increase of cold could render 

 this possible, inasmuch as there could not be a sufficient 

 influx of vapour to produce the necessary condensation ; 

 and the greater the cold, the less would be the evaporation. 

 On the other hand, any increase of heat would be felt more 

 rapidly in the thawing and evaporation of land ice and snow 

 than on the surface of the sea. 



Applying these very simple geographical truths to the 

 North Atlantic continents, it is easy to perceive that no 

 amount of refrigeration could produce a continental glacier, 

 because there could not be sufficient evaporation and preci- 

 pitation to afford the necessary snow in the interior. The 

 case of Greenland is often referred to, but this is the case of 

 a high mass of cold land with sea, mostly open, on both sides 

 of it, giving, therefore, the conditions most favorable to pre- 

 cipitation of snow. If Greenland were less elevated, or if 

 there were dry plains around it, the case would be quite 

 different, as Nares has well shown by his observations on the 



1 These views have been admirably illustrated by Von Woeickoff 

 in the paper already referred to and in previous geographical papers. 



