the eastern base of the main range it lies quite unconform- 

 ably on the Hokanui and older rocks, and, according to Dr. 

 Hector and Dr. von Haast, it is also found in a similar posi- 

 tion on the West Coast ; thus lying at a low level almost on 

 the main anticlinal axis. The Waipara System lias itself 

 been much disturbed in Nelson and in Otago, and is every- 

 where denuded and overlain unoonformably by beds of the 

 Oamaetj System (Oligocene) and Pakeqra System (Miocene). 

 Outliers of these cretaceous and tertiary rocks are found far 

 up the Alpine Valleys, reaching a height of 3,000—4,000 feet 

 above the sea, but they do not take part in the folds of the 

 older rocks. Volcanic rocks, chiefly acidic, belonging to the 

 Waipara System, lie along the eastern flank of the mountains 

 in Canterbury from Mount Somers to the Malvern Hills, and 

 later volcanic outbursts took place in the Oligocene and 

 Miocene periods. In the South Island volcanic action appears 

 to have become extinct in the Miocene ; the focus of energy 

 changing to the North Island, where it has not yet quite died 

 out. 



The probable geological history of the New Zealand 

 Alps is as follows : — The volcanic outbursts which took place 

 during the deposition of the Maitai System, and which we 

 now recognise in the row of granite hills along the centre of 

 the main anticline in Westland and Nelson, as well as in the 

 greenstone ash beds associated with the sandstones and mud- 

 stones of the system, may perhaps be taken as the first step 

 towards the formation of the New Zealand Alps. This must- 

 have been followed, or accompanied, by elevation and suffi- 

 cient denudation to lay bare the granitic roots of the 

 volcanoes. A range of mountains must have been formed 

 lying to the west of New Zealand. Their height must have 

 been immense, rivalling probably the Himalaya ; for, during 

 the subsequent deposition of the Hokanui System, a subsi- 

 dence of more than 20,000 feet took place, and yet land must 

 always have been in the neighbourhood, for plant remains 

 are found throughout the system. At the close of the 

 Hokanui period lateral compression, accompanied by upheaval, 

 took place along a line to the east of the earlier chain, and 

 the main outlines of the New Zealand Alps were formed. It 

 was then that New Zealand was separated from Tasmania, 

 and the two have never been connected since. A long period 

 of subaerial denudation succeeded, during which the greater 

 part of the west wing of the main anticlinal was removed, 

 and most of the present river valleys were formed. When 

 this elevation was at its height, volcanic eruptions broke out 

 along the eastern (and perhaps western) side. Depression 

 followed, and the Waipara System was deposited round the 

 coasts. Again, a third elevation took place, accompanied by 



