Otago hisHtute. 



Sixth Meeting : 22nd September, 1909. 

 Dr. Fulton in the chair. 



Papers. — 1. " The Great Ice Age of New Zealand," by Proiesfcor James 

 Park. V 



In this paper the author summarised[^the evidences of glaciation seen in the Waka- 

 tipii region, on the east coast of Otago between the Clutha and Waitaki, in Canterbury 

 and Nelson. A detailed description was given of the Taieri moraine, and Kaikorai 

 glacial dejiosits near Dunedin, and of the boulder-till covering the Hautapu Valley along 

 the Main Trunk Railway in Wellington. He contended that Dr. Marshall was in error 

 in saying that a boulder-clay was relatively thin because formed under the ice. In 

 North America the tills are found 500 ft. thick, and in Germany 670 ft. thick ; while a 

 Permo-Carboniferous till found in South Australia is 1,500 ft. thick. Besides, tills are 

 not uniform and continuous sheets, but notoriously irregular. The beautiful, smooth, 

 flowing contours of Otago were the result of ice erosion, as stated by J. T. Thomson in 

 1875. South America was glaciated for 1,400 miles north of Cape Horn, up to latitude 

 37° S., and he thought the evidence conchisive that New Zealand had participated in 

 the general glaciation of the Southern Hemisphere. Captain Hutton, in his glacial 

 map of New Zealand, showed nearly half of the South Island covered with a continuous 

 ice-sheet. The author believed there was now sufficient evidence to warrant the belief 

 that the greater portion of the Island was glaciated. He thought the glacial period of 

 New Zealand was due to elevation, which increased the area to continental dimensions, 

 and linked it up with the outlying southern islands, at the same time diminishing the 

 width of sea to the Antarctic. The New Zealand ice-sheet would radiate from the 

 elevated centre of movement towards the sea, and would thus meet the advancing polar 

 ice, which would, however, be kept off the New Zealand shores by the superior thrust 

 of the land-ice. 



Mr. G. M. Thomson advanced several reasons from the botanical point of view 

 against the theory that a glacial epoch prevailed in Pleistocene times in New Zealand, 

 and that what now constituted the Soutli Island (which, according to Professor Park, 

 was only separated during that epoch) was then covered witJi an ice-sheet. (1.) The 

 flora of New Zealand contained, accordmg to Cheeseman, 332 genera and 1,415 species 

 of flowering-plants. Of this number 2 genera {Stilbocarpa and Pleurophyllum) and 

 45 species are peculiar to the Antarctic Islands (Macquarie, Campbell, Auckland, 

 Antipodes Islands, and the Snares) ; while 26 genera and 452 species are found in the 

 South Island and Stewart Island, but do not range into the North Island. These peculiar 

 South Island forms included such aberrant types as Ranunculus Lyallii, the wliipcord 

 Veronicas, the vegetable sheep {Baoulia eximia and mammillaris), the remarkable woolly 

 Haastias, and many other singular plants. They formed one of the most interesting 

 collections to be found in any part of the world. He argued that the extraordinaiy 

 diversity of form and type which prevailed among these genera and species recjuired a 

 very considerable period of time for its development, and that the differentiation pro- 

 bably dated from an era much antecedent to the Pleistocene. (2.) One of the effects 

 of recent glaciation in the Northern Hemisphere was to produce among the woody plants 

 a deciduous type, such plants only, luiless specially modified for the purpose, being able 

 to resist the destructive effects of snow. Taking Britain as an example of an area 

 glaciated within recent geological times, he found tliat of the 1,223 species of flowering- 

 plants in its existing flora, only 91 (or 7-4 per cent.) were trees or shrubs. Of these, 

 26 (or 28-5 per cent.) were evergreen, but these included all the small-leaved or hard- 

 leaved species, such as Scotch fir, juniper, yew, heaths, gorse, &c., which were not injured 

 by snow. The only soft-leaved evergreen in Britain was the ivy, which did not hurt 

 with snow. All the other trees and shrubs, to the number of 65 (or 71-4 per cent, of the 

 whole), were deciduous, losing their leaves on the approach of wmter, and so being 

 miinjured by snow. In New Zealand, out of the 1,415 species of flowering-plants, 450 

 (or 31-8 per cent.) were trees or shrubs. Of this number, 398 (or 88-3 jier cent.) were 

 evergreen, 45 (or 10-1 per cent.) were leafless, while only 2 species of Fuchsia were abso- 

 lutely, and 5 other plants partially, deciduous — that is, at the outside, less than 1-5 per 

 cent, were fitted to withstand the destructive effects of snow. In the face of these; facts 

 it is impossible to conceive that this Island had a glacial epoch within recent times. 

 (3.) There exists in New Zealand, and especially m the South Island, what is called a 

 xerophytic or desert flora — a group of plants specially modified to withstand drought. 

 These are prmcipally found on the momitain-slopes and on the plains on the eastern 

 side of the mam range of mountains formmg the backbone of the South Island. The 

 speaker showed the effects of this range on the moisture-laden winds which sti-ike the 



