Canterbury and Westland. 383 



In the first instance the plateau-like ranges would rise still 2000 feet 

 higher above the sea level than assumed by me, and consequently the 

 size of the snow-fields would not only become of still larger extent, but 

 for this reason would descend to a still lower position. At the foot of 

 these high ranges a plain of considerable extent, sloping gently down- 

 wards to the sea, would surround the three islands and unite them 

 into one, Cook's and Eoveaux Straits forming both broad valleys. In 

 these plains a luxurious vegetation would spring up, offering ample 

 nourishment for a great number of birds, of which the extinct Dinor- 

 -nitJiidce were forming the most conspicuous part During such 

 physical aspect of the land these large birds would have found an 

 almost unrestricted passage from one part of the united New Zealand 

 to the other. Moreover, peculiar climatological conditions then 

 reigning would soon slightly differentiate the species, to become still 

 more decided when through the rising of the ocean the valley of 

 Cook's Straits would again become an arm of the sea. Such a sub- 

 mergence would, if the theory in question is correct, have occurred at 

 different times, judging from the fact disclosed to us, that the glaciers 

 repeatedly advanced and retreated. Consequently, along the East 

 Coast the glacier torrents would build up their great shingle fans, 

 gradually decrease in velocity and flow at last as broad rivers through 

 rich gently sloping lands for a considerable distance. A different state 

 of things would obtain at the West Coast ; here the retreat of the sea 

 would also lay dry a belt of slightly sloping level land along the base 

 of the Southern Alps, and over it the large glaciers would advance 

 fifteen to twenty miles, throwing up their lateral moraines on both 

 sides. The ocean rising again, so as to assume its former level, the 

 waters would of course advance between the morainic accumulations j 

 the same process as already described would then take place. Shingle 

 and sand-bars with lagoons, often of considerable extent, behind 

 them, would be formed. These lagoons would gradually be filled up 

 with decaying vegetation and the accumulations of fluviatile character 

 brought down from the slopes of the mountains forming their eastern 

 boundary. Although, as before observed, I am not as yet in a position 

 to pronounce for or against Mr. Belt's theory, I have nevertheless 

 thought it only right to show that, so far, all the physical conditions 

 of Xew Zealand during the Great Glacier period, and the abundant 

 animal life then existing, could be explained by it, and I shall leave it 

 to future days to adopt or reject this ingenious theory, when still more 

 facts have been accumulated and more light thrown upon this interest- 

 ing period of the Earth's history. 



