Hill. — Geology of Hawke's Bay. 469 



wider the temperature contrasts between any two zonal regions 

 the greater must be the quantity of heat which passes between 

 them. But although the earth was warmer and the sun gave 

 out more heat to the earth in Pleistocene times, it does not neces- 

 sarily follow that the climate of Europe, America, and Austral- 

 asia was warmer than now. Climate is the average state of 

 the weather in any district or country based on a long period 

 of observations, but the causes which regulate the weather are 

 by no means well understood, as the people of Hawke's Bay 

 have been made fully aware during the past twelve months. 

 The great modifiers of climate are latitude and elevation ; but 

 there are other modifiers, which, though second to those 

 named, have yet an important influence on the climate of a 

 country. At the present time Europe maintains but few 

 glaciers except in the Alps and northern Scandinavia, and 

 none are met with in any portion of the British Isles. During 

 the Glacial period nearly the whole of western Europe is said 

 to have been covered with ice, and, as already pointed out, the 

 period is said to have been one mainly of submergence. None 

 of the Alpine glaciers now descend below the level of 4,000ft. ; 

 there are no glaciers in North America of large size or de- 

 scending below the 4,000ft. level ; so that it may be supposed 

 the climate of Europe in Pleistocene times was from 10° to 15° 

 below the average temperature of that continent at the present 

 time. 



Considering the latitude of the area in which glaciation is 

 said to have taken place, it seems that some causes which do 

 not now exist must have operated to produce such unusual 

 climatic contrasts as are said to have characterized the 

 Pleistocene period of Europe and America. The difficulty 

 which presents itself here is not so much in the wide exten- 

 sion of the glaciers as in the vast amount of condensation that 

 must have taken place beyond the snow-line, in order to pro- 

 vide a neve ox fir n for the supply of the glaciers. For a glacier 

 is -imply an ice river below snow-line with its source above 

 snow-line, and the very fact that glaciers exist is evidence 

 in itself that below the snow-line the temperature is more 

 than sufficient to melt the ice were the supply from the neve 

 not so great. The movement of the Franz-Josef Glacier in 

 New Zealand to within 700ft. of the sea-level, and far below 

 the limit of perpetual snow, shows that such a thing is possible. 

 But a glacier of this kind is clearly dependent on some special 

 cause. It is not possible to conceive of a glacier unless on 

 the assumption of a source of supply in a region where water 

 is never found other than in one of its crystallized forms. The 

 " snow-line" implies that everywhere above that line the tem- 

 perature of the air is such that condensation produces either 

 snow or hail. Cut off the supply or neve from the Franz- 



