Otagu Institute. 543 



■were as old as any rocks on the surface of the earth. In other words, 

 they had a position with regard to old rocks that occurred on their flanks 

 that indicated that they were of the highest antiquity. They were formed 

 probably when conditions on the earth's surface were entirely different 

 from what they are now — at a time, probably, when no life at all existed 

 on the surface of the earth, and when all was void. Rocks that were once 

 in a molten state at an extremely remote period were found in other parts 

 of New Zealand. Some of these rocks were of exceptional interest, being 

 very much heavier than the ordinary surface rock. Their density indicated 

 that at one time thej' were resident probably two hundred miles beneath 

 the surface, and their presence in abundance in certain quarters pointed 

 to the fact that New Zealand at one time in its history was subject to 

 tremendous disturbances. If volcanoes were connected with that extreme 

 pressure they had now disappeared. Near the Bluff and elsewhere rocks 

 were found that were once volcanic rocks, but where the volcanoes were 

 that these rocks came from was not known. The Carboniferous beds 

 formed an important part of the structure of New Zealand, and a study 

 of them led one to conclude that there must have been an enormous amount 

 of volcanic action in this country jirior to the Carboniferous age. It was 

 of interest to conjecture where this volcanic land was. The actual Car- 

 boniferous rocks must have been on the sea-shore at that time, and the 

 whole of New Zealand seemed to have been a sea-shore, bounding some 

 volcanic country. Those who had investigated the question most fully 

 were doubtful whether the land extended to the east or to the west. 

 ■Obviously the easiest way to come to a conclusion was to find out where 

 the sediments were coarsest — on the east or on the west — but as far as that 

 was concerned there did not seem to be very much difference in them. 

 Sir James Hector favoured one view, and Sir Julius von Haast the other 

 So far as his own limited observations had enabled him to come to a con- 

 clusion, he thought it was likely that the land extended a greater distance 

 to the east than to the west. This, as he had said, was in the Carboniferous 

 days, when New Zealand was nothing more than the coast-line to some 

 huge continental area, from which rivers were constantly bearing down 

 great volumes of water, and carrying to the coast line immense quantities 

 of sediment. This sediment had compacted, and now formed much of 

 the country of New Zealand. For a long time after that there was no 

 •evidence of volcanic action, but about the beginning of the Tertiary period, 

 when mammalian life was beginning to assert its dominance in the animal 

 world, some disturbance took place on the east side of the Alps. The 

 actual volcanoes had themselves disappeared, but the nature of the rooks 

 •clearly indicated that there was volcanic activity of some intensity over 

 the surface of the land in those days. In all probability the rocks on 

 Coromandel Peninsula were thrown up at the same time. Then there was 

 little evidence of any other action until the Miocene period, when there 

 was verj' widespread activity throughout the greater part of New Zealand. 

 It was about this time that the Dunedin volcanic area was formed. This 

 area, he pointed out, presented some peculiar features in its igneous rocks. 

 One rock was heavy and another light, and there were also important differ- 

 ences in colour and in the crystallized structure. Red and black rocks, and 

 sometimes white rocks, were found side by side. Did these rocks come frou) 

 tlie same volcano or from the same reservoir ? So far there was no satis- 

 factory explanation of any cause that would produce differently coloured 

 and differently natured rocks from the same volcano. In this district, 

 again, there were evidences of considerable intervals between the periods 

 of volcanic eruption. At Anderson's Bay, for instance, on the northern 

 side of the bay, the lower portion of the cliff was soft, while the rock lying 

 -over it was hard. They were both volcanic rocks, and were hard at the 

 •time they were emitted, but an enormous time had elapsed between the 



