500 Transactions. — Geology. 



period of New Zealand was contemporary with the glacial 

 period of northern continental Europe. 



Of the maximum elevation reached we know nothing. 

 One thing, however, is certain — namely, that as soon as the 

 maximum elevation was reached the sinking of the land at 

 once set in. The glaciers now began their retreat to the 

 main divide, and at this time the great Southland, Canter- 

 bury, and Moutere* gravel plains were formed on the gra- 

 dually sinking surface of the land. Thus we find that New 

 Zealand since the close of the Secondary period has been 

 rising and sinking with singular regularity. 



The South Island of New Zealand at the close of Eocene 

 consisted of a long narrow mountain-chain with many de- 

 scending ridges and outlying rocky islets. The watershed, 

 was so narrow that no large streams existed, while the sink- 

 ing of the land lessened the height of the dry land and cor- 

 respondingly decreased the velocity of the descending meteoric 

 waters. Torrential streams were absent, and denudation of 

 the land was comparatively slow. The Tertiary deposits were 

 laid down on the floor of the open sea, and in all the bays, 

 deep indentations, and long fiords existing at the time ; 

 and everywhere the same conditions of quiet deposition ap- 

 pear to have existed. 



The uniformity of the contained fauna is not less 

 remarkable than the uniformity of the sediments. Some 

 localities yield forms that are specially distinctive of the 

 place, but it is notorious that the characteristic fossils of 

 each horizon are the same from one end of New Zealand to 

 the other. 



In the majority of places near the coast the Tertiary beds 

 are lying flat, or are only slightly inclined, except where 

 faulted, or disturbed by igneous intrusions. In the neigh- 

 bourhood of Lake Wakatipu, and along the flanks of the 

 Kaikouras in Marlborough, they are nipped up and entangled 

 among the older rocks by extensive faulting. But the in- 

 volvement is not great, and, in the case of the Kaikouras, of no 

 structural or tectonic importance, as is clearly shown where 

 the sections are drawn to natural scale. 



Manifestly the main orographical features of the country 

 were determined after the close of the Jurassic period — a view 

 which receives support from the distribution of the Waipara 

 series, which was apparently deposited as a marginal beach on 



* The Moutere gravels, which rise from sea-level at Golden Bay 

 to a height of over 2,000 ft. at the Hope Saddle, wore formed by the 

 IWotueka at the time that river drainod the north-west slopes of the 

 St. Aruaud and Spencer Mountains. The Buller River by its rapid 

 recession intercepted the head-waters of the Motueka, which is now 

 greatly diminished in volume. 



