412 Transactions. — Geology. 



lateral valleys becoming more extended from day to day, would furnish more 

 and more material for the formation of huge moraines. 



(G.) " Let us now consider what may have been the action of the waters 

 during the emergence of the island upon the region over which at present the 

 Canterbury plains extend. 



(7.) " In the first instance the waves of the sea would have acted upon 

 the tertiary strata, undermining and destroying them, till the debris of the 

 falling cliffs would have formed a protecting wall at their foot, although 

 frequent oscillations and changes in the ratio of elevation or subsidence may 

 have caused many diversities. 



(8.) " The tertiary beds, risen above the level of the sea, would soon have 

 been eroded' by the action of the streamlets or torrents descending from the 

 higher regions, and growing larger with the continuance of the upheaval and 

 becoming more numerous, bringing down with them gi'avel and sand, more 

 effectually increasing their eroding power. 



(9.) " At the same time the glaciers, descending from the enormous snow 

 fields, covering the large plateau-like ranges, began to fill all the existing 

 valleys to the plains in a fan-like shape. 



(10.) " Of tliis occurrence, however, we have very little proof, if it be not 

 that the older glacial deposits in the bed of the Kangitata, several miles below 

 the gorge, and some others rising above the plains, between the Malvern Hills 

 and the Waimakariri, belong to that period. 



(11.) "High on the ranges, near the plains, the proofs of still greater 

 glaciation of the island are visible in the in worn sides ; even the ranges 

 themselves, in their summits and configuration, bear distinctly marks that their 

 very form is attributable to such an almost universal glaciation. Moreover, 

 it is evident, by judging from the study of our present glaciers, that these 

 enormous n^ves, and ice masses, covering with an uniform sheet the higher 

 regions of the whole island, would not offer much material for the formation 

 of the plains till the glaciers had begun their task of ridge-making, which 

 took place principally in the second epoch of the glaciation of this island. 



(12.) "The glaciers had so far retreated that they were only confined to 

 the principal valleys, and of these such clear signs are found, as soon as we 

 enter the valleys between the ranges leading from the Canterbury plains into 

 the Southern Alps proper, that their power and its effects are unmistakable. 

 And as now these glaciers, as shown above, brought a much greater amount 

 of debris from the disintegration, destruction, and weathering of the mountains 

 with them, they did not form only enormous moraines at their sides and their 

 terminal end, but the torrents issuing from them carried down a great amount 

 of material in tlio form of boulders, shingle, sand, and glacier mud, the latter 

 being derived from the triturating effects of the ice on the sides and bottom of 



