69 



precipitation of snow on the leading peaks of the region." So in 

 Canada, and in the Ottawa district, a great reduction in the tempem- 

 ture followed the great elevation, and immense quantities of snow, ice 

 and water followed and glaciers were formed all over the district a vast 

 mer-de-glace covered this portion of Canada, whose height above the 

 ocean level of that period was considerable. These glaciers, like modem 

 ones, were characterized by many interesting particulars which a study 

 of the latter can afford. The number, dii'ection, movements, thickness, 

 erosive or denuding power and the constituent parts of a glacier, or a 

 system of glaciers, are questions full of interest. It has been ascertained 

 that over four hundred glaciers can be seen in the central portion of the 

 Alps, from Mont Blanc to the Tyrol, some of which are only three miles- 

 in length, whilst others exceed twenty miles from head to foot or from 

 the point of origin to the snout. There is abundant evidence to show 

 that the number of glaciers which must have existed here about Ottawa 

 is vej-j considerable. Pei'haps the greater number, were subor- 

 dinate or small ones and may, at length, have been absoibed in and 

 formed part of " a great glacier." The direction in which they moved 

 de2)ended of course on the nature of the district, its pliysical or 

 orogra})hical character. The general trend of the great mer-de-glace in 

 Canada during this epoch has been ascertained to be approximately 

 N. E. and S. W. With regard to the direction of some of the glaciers, 

 the striations or grooves on the rocks about Ottawa show that in 

 some cases they travelled almost due east and west, as may be seea 

 along Park Avenue, on Nicholas street and in other parts of the city, 

 at other times they appear at a considerable angle to this direction, 

 bearing almost due north and south, as at Buckingham on the Lievre 

 River. Regarding their movements and the s])eed with which glaciex-s 

 travel, we consult Agassiz and find that he obtained the following results 

 in 1841 and 1842 on some of the Aar glaciers : 



I. FiNSTEU Aar ' annual 



MOTION. 



Stake near centre of glacier HCii* feet. 



" side " IGU " 



{ 



II. Lauteu Aar 



Stake nearest centre of glacier 245 



'- side " 124 



I 



