Canterbury and Westland. 401 



lagoon, of which Lake Ellesmere is only a remnant. Of this occur- 

 rence we have sufficient evidence in the immediate neighbourhood of 

 Christchurch and Kaiapoi ; and still up to the present time the topo- 

 graphical features of the ground which rises close to the western foot 

 of Banks' Peninsula, only about twenty-six feet in its highest neck 

 above the sea, having on both sides low swampy ground, would give 

 additional evidence to such a theory, were not other proofs sufficient 



\ have already pointed out that there has been an oscillation of about 

 twenty feet, the upward movement occurring towards the end of the 

 Great Grlacier period. This rising of the country was of course of 

 great importance for the low ground forming in front of the shingle 

 fans. Thus with the rising of the country this large lagoon became partly 

 filled either by the shingle of the rivers falling into it, (of which the 

 "Waimakariri was the most important in throwing its fan nearly across 

 it), or assisted by the silt which the rivers had in suspension, and which 

 was thrown down all over the lagoon in the form of loam and clay. 

 Moreover, drift sands invaded it from its eastern shore, coming from 

 the north, giving additional breadth and stability to the banks which 

 separated it from the Pacific Ocean. At favourable localities, just rising 

 to or near the surface of the water, vegetation began to spring up, 

 forming swamps, which with the assistance of bog-mosses {Sphagnum) 

 and other aquatic or semi-aquatic plants forming peat, raised consider- 

 ably the ground, so as to form a suitable locality for the beginning of 

 forest vegetation. Many were the slight oscillations taking place, 

 through which the rivers changed their channels, and either removed 

 the clays deposited in the lagoon, or buried below their newly-forming 

 shingle-beds the peat swamps, vegetable soil, and even forests, of which 

 well-sinking in the neighbourhood of Christchurch has offered many 

 illustrations. In this way those swamps were either covered or partly 

 drained, whilst others, not so favourably situated, continue to this 

 day to remain in the same condition, as, for instance, portions of the 

 Rangiora swamp. Many of the raised beaches are easily traceable, 

 and with them the former western banks of the great Lake Elles- 

 mere extension. This accounts also for many peculiarities we meet in 

 the centre of this ancient, partly drained and filled lagoon, which, 

 without such an explanation, would be unaccountable. 



It has been before stated, that the declivity of a river diminishes in 

 proportion to the distance it has to run from its source, and it is thus 

 natural that the rivers now traversing the Canterbury plains have 



