OTAGO INSTITUTE. 



First Meeting: llth May, 1909. 



Professor Park, President, in the chair. 



The following is a sumniarv of the presidential address by Professor 

 Park, entitled " The Glaciation of Otago " :— 



The lecturer stated that, in accordance with instructions received, he made, in tlrree 

 successive years, a geological survey of Central Otago, commencing at the Maniototo 

 Plain and working westward to Wakatijni. He discovered that Central Otago was 

 occupied by a remarkable group of block mountains, which were table-topped, and 

 bounded by powerful dislocations. Pi-actically all the mountains in Central Otago 

 were so distinguished— the Hawkdun, Dunstan, Pisa, Carrick, Garvie, Old Man, and 

 Umbrella Ranges being typical exami>les. 



The origin of these mountains was pecidiar, and, in themselves, they belonged to 

 a iinique and distinctive tyjie, without a parallel elsewhere in the Southern Hemisphere. 



But before considering the origin of these block mountains they might first look at 

 the ordinary type of moiintains, with which every one was familiar, as, for example, 

 the Alps of New Zealand or of Europe, or the American Sierra Nevada, or the South 

 American Andes, the summits of which, were irregular and deeply serrated, and often so 

 narrow as to form a mere razorback. Examination of their structure showed that 

 the rocks of which they were composed M'ere arranged in folds, often very complex. 



Geologists the world over had offered exjilanations of the peculiar formation of 

 block mountains, but only two of these latter were worth considering. Professor Suess, 

 of Vienna, conceived a great plateau or plain, which he considered had been broken up 

 by great cracks or fissures. Certain sections had, by a siibsidence, been left at a much 

 higher level than others, with the result that they now had, with all sharj) corners worn 

 off, the table-topped mountains and intervening basins. 



Professor Davis, of Harvard, on the other hand, postulated a plain at or about sea- 

 level, cracked by great dislocation, and subjected to unequal uplift. 



These were the theories that had been formed regarding the very remarkable 

 mountains of Central Otago, mountains that distinguished New Zealand, and which 

 would in future years attract many scientists to the Dominion. Tlie whole of Central 

 Otago was occupied by these fiat-topped mountains, on which a person might, in some 

 cases, conveniently ride for over a Inmdred miles. 



The lecturer next directed attention to the glaciation of New Zealand. Dviring the 

 progress of his geological work he had been fortunate enough to obtain evidence to show 

 that New Zealand at one time had a glacial period similar to that of the Northern Hemi- 

 sphere. He had been able to prove that Otago and the greater jiart of the South Island 

 were covered with a continuous ice-sheet — probably an extension of the south polar 

 ice. In the Wakatipu basin the ice in thickness exceeded 7,400 ft., this immense glacier, 

 it would appear, being fed by three streams. It had flowed over the top of Mount 

 Nicholas, which had been cut into tlie shape of an immense dome, beautifully rounded 

 and smoothed, and flanked by beautiful U-shaped valleys. 



Every one had heard of the glacial period of the Northern Hemisphere, often spoken 

 of as the Great Ice Age, that took place in the Pleistocene — the period which in'eceded 

 that in which we live — the geological yesterday'. The north polar ice invaded North 

 Europe, northern North America, and North Asia, and steadily advanced until it reached 

 latitude 50°, carrying with it destruction and desolation. 



The forests were overwhelmed and completely obliterated, while the animals and 

 men inhabiting these continental areas retreated southwards before the terrible blighting 

 wall of ice. But animals in the insular areas, being unable to escape, sought refuge 

 in caves and holes in the earth, and there miserably perished. In Western Europe the 

 ice-wall covered Norway and Sweden, the whole of Scotland, and the greater ])art of 

 England. In Scotland the maximum thickness was 5,000 ft., and in Central Europe 

 7,000 ft. 



In course of time this ice-sheet retreated, and left the features of the land curiously 

 altered. The mountains, ridges, and simrs were ground downi and truncated, the valleys 



