Canterbury and Westland. 37S 



the line of perpetual snow, the accumulation of neves began, being the 

 more considerable as glaciers and large rivers had not yet begun then- 

 task of ridge making, in contradistinction to the action of waves and 

 currents of the sea, on submerged lands, tending to wear off all emi- 

 nences, and filling the submarine valleys with the debris. Another 

 important cause for still greater accumulation of enormous neves must 

 be assigned to the fact, that when the country had risen to its present 

 level during the Glacier period, the drainage channels were only very 

 imperfectly formed, consequently, a very serious impediment for the 

 flowing off of the glaciers was first to be overcome before the snow- 

 fields could get rid of their annual increase. If we admit that only 

 the same amount of atmospheric precipitation fell in the plateau-like 

 ranges, as at the present time — about 115 inches in Holdtika and 100 

 inches at the Bealey — and that it took, to say the least, only a few 

 centuries before the drainage system was properly developed, and 

 supply and discharge somewhat balanced, it is evident that the snow- 

 fields must have assumed such enormous proportions that we can 

 scarcely form a conception of their dimensions. When once the 

 channels were formed, or the proper outlet was reached, the vis a tergo 

 of the ice mass must have been of inconceivable power. That there 

 was a blocking up of the ice masses in many portions of the Southern 

 Alps is clearly shown by the anastomosing of the glaciers, of which 

 the Eakaia, Ashburton, and Eangitata form notable instances. 



Eeturning to the physical features of the country at the beginning of 

 the Great Glacier period, it is evident that the configuration of the area 

 now forming the Canterbury plains would have been a broad arm or 

 channel of the sea running along cliffs of tertiary rocks from Timaru 

 to Double Corner, and surrounding Banks' Peninsula as an island, 

 whilst at the "West Coast the ocean would have reached generally to 

 the very foot of the Southern Alps. As before observed, the waters 

 derived from atmospheric sources had only partly begun during the 

 emergence of the land to open an outlet for themselves from the 

 higher regions, cutting at the same time into the tertiary strata, which 

 filled in favourable localities pre-existing valleys, and skirted the foot 

 of the Alps to an altitude of 4000 feet. Under these circumstances 

 the neves — considering the insular and peculiar condition of Xew 

 Zealand, its principal range or backbone running from S.W. to N.E., 

 therefore lying at right angles to the two principal air-currents the 

 equatorial N.W. and the polar S.E., both bringing moisture with them 

 ■ — soon attained such an enormous extent, even if we do not take the 



