The Laivs of Climatic Evolution. — Manson. 51 
Brief Review of Past Climatic Conditions. 
The evidence of rising temperatures since the Ice age. 
The elementary laws of climatic evolution having been 
briefly deduced and formulated, it may be necessary to re- 
vert 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 ele- 
vation 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 previous extension. It matters not 
whether the glacier be the dwarfed remnant left on the summit 
of the mountains of tropical Africa* or South America! or 
the great glaciers of Alaska or Greenland, t- once greater ex- 
tension is a characteristic and general fact noted by all ob- 
servers. 
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 becomes fainter; the 
traces of this action are more modified 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 sea on the west coast of North America. Here in 
latitude 40 to 45 degrees, the geologist finds types of topog- 
raphy built up or shaped by ice action, yet' so modified and 
buried beneath successive growths of conifers that onlv the 
trained eye of the close observer can follow the forms and 
features. In the next few degrees northward, the work of 
the glacier is less modified and hence more distinct. Great 
*Mt. Kenia Quart. Jour. Geo!. Soc. Vol. LI. No. 204, pp. 67S-6 
G. F. Scott Elliott. 
fTravels among the Great Andes of the Equator, p. 62. Note. 
Whymper. 
JThe Glaciers of North America, Prof. I. C. Russell. See also 
authorities quoted by Prof. R. 
Report on an Exploration in the Yukon District of the N, W. Ter- 
ritory. 
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. 
