12 



BRIEF REVIEW OF PAST CLIMATIC CONDITIONS. 



THE EVIDENCE OP RISING TEMPERATURES SINCE THE 

 ICE AGE. 



The elementary laws of climatic evolution having 

 been briefly deduced and formulated, it may be neces- 

 sary to revert to the geological record of past climatic 

 conditions, and to note whether they agree with these 

 laws. 



Commencing at sea level near the polar circles, at an 

 elevation of a few thousand feet above this level in 

 temperate latitudes, and at a still greater elevation in 

 tropical latitudes glacial ice is found to rest upon the 

 land. Adjacent to this ice are found evidences of pre- 

 vious extension. It matters not whether the glacier be 

 the dwarfed remnant left on the summit of the moun- 

 tains of tropical Africa* or South Ameriaf or the great 

 glaciers of Alaska or Greenland, J once greater extension 

 is a characteristic and general fact noted by all observers. 



The evidences of this retreat near the base of the 

 glacier -is not disputed. But as the distance from the 

 living glacier increases the evidence of ice action be- 

 comes fainter; the traces of this action are more modi- 

 fied by decomposition and denudation and more deeply 

 covered with vegetable mould, as we recede either in 

 altitude or latitude from the living glacier. Nowhere 

 is this better marked than at uniform levels above the 



* Mt. Kenia Quart. Jour. Geol. Soc, Vol. LI, No. 204, pp. 675-6. G. F. 

 Scott Elliott. £ 



t Travels among the Great Andes of the Equator, p. 62. Note. Wymper. 



t The Glaciers of North America, Prof. I. C. Russell. See also author- 

 ities quoted by Prof. R. 



Report on an Exploration in the Yukon District of the N. W. Territory. 



Part B, Annual Rep. 1887, pp. 51-58, Geol. and Nat. History of Canada. 



Am. Geologist, Vol. XIX, No. 4, p. 263. 



Am. Geologist, Vol. XX, pp. 329-330. 



