Otago Institute. 81 



have destroyed all canimals and all plants in these Islands, and, since they had not been 

 in connection with any land-surface since the Pleistocene, it was impossible for them 

 to have been peopled since that date. Moreover, the species of land-birds on the Auck- 

 land Islands were distinct from those of New Zealand. It was not a question merely 

 of their annual flight after the withdrawal of the ice-sheet. That was quite possible, 

 for several introduced birds were observed, but the differentiation of species in these 

 outlying islands was great, and all indicated a long separation ; while the presence of 

 the fliglitless duck, a genus found nowhere else, was even more impressive. As a result 

 of the recent expedition they found, from an examination of the various groups of inverte- 

 brates, that, although there were similarities to those in New Zealand, many of them 

 were more nearly allied to South American forms, which could not by any possibility 

 have survived an ice-sheet, or have arrived here after the ice-sheet had withdrawn. It 

 was only possible to explain the occurrence of such existing terrestrial forms, which 

 could neither fly nor swim, which could not survive a sea-bath, by their migration along 

 a land-area extending across the Antarctic region from South America to tliese Islands. 

 It seemed to him that the onus lay with Professor Park to show how these subantarctic 

 islands became peopled after their fauna and flora had been wiped out by the Pleistocene 

 iice-sheet. The whole biological evidence seemed to be entirely antagonistic to his theory. 

 " Moreover," he said in conclusion, " I believe that the thesis can be strongly supported 

 that there was no general reduction of temperature over the whole Southern Hemisphere 

 at or about that period." 



Professor Marshall also criticized Professor Park's conclusions adversely, his sum- 

 mary and conclusions being as follows : — A. That an ice-sheet did not reach the east 

 coast of the South Island is ]>roved by — (1.) The absence of moraines near the coast, 

 except at the landward end of the Taieri Gorge, where there have been important earth- 

 movements. (2.) The absence of tiU and boulder-clay. The substances that have 

 been claimed as belonging to this class are — (a) loess in Canterbury and north Otago, 

 (h) residual clays from volcanic rocks at Dunedin, (c) moraine and valley-trains at the 

 Taieri, [d) old sea-beaches at Caversham and at Green Island. (3.) Absence of roches 

 moutonne.es. (4.) Absence of striated glacial pavements. (5.) Absence of erratics and 

 of striated boulders. (6.) Absence of a glacial topography in all coastal districts. 



B. The ice of the Wakatipu glacier. (1.) The occurrence of ice in one valley does not 

 justify the conclusion that the neighbouring valleys were ice-filled. (2.) The thickness 

 of the ice in the ancient Wakatipu glacier appears less impressive when it is realised 

 that the ice in the Tasman Glacier is at the present day over 2,000 ft. thick, and that 

 its base is only 1,600 ft. above sea-level. (3.) If the ice was 7,940 ft. thick at the Hector 

 Mountains and if it had the same surface-slope as the Greenland ice-sheet, it must have 

 extended far over the tops of all the western mountain-peaks, which, however, are not 

 glaciated. (4.) The reversed slope of the Wakatipu basin must have existed during 

 the glaciation. This implies a rapid thiuning, which must have been due to melting. 

 Adopting the surface-slojie of the Greenland ice-sheet, the terminal face cannot have 

 been east of Lumsden. (5.) The author's estimate of the level of the surface of the 

 ice is 4,000 ft. at Mount Dick. The terminal face would then be at Athol. (6.) There 

 is no ice erosion on the Hokonui Hills, and no moraine or erratics in the Waimea Valley. 



C. The suggested extension of the Antarctic ice-sheet. (1.) At the present time the ice 

 nowhere extends into deep water. (2.) There was no ice-sheet in Siberia when there was 

 an ice-sheet in ceiitral Europe, or in Alaska when the Mississippi Valley was glaciated. 

 (3.) America was not all glaciated simultaneously. (4.) A reduction of temperature in 

 South Victoria Land would cause a decrease of glaciation. (5.) There is an absence of 

 all effects of an ice-sheet at the Campbell and Auckland Islands. (6.) No erratic blocks 

 from South Victoria Land have yet been found in New Zealand. D. The suggested glacia- 

 tion of the North Island is disproved by the following : (1.) The mapping of the river- 

 coxirses shows no indication of the existence of a glacial topography. (2.) No striated 

 rock-surfaces. (3.) No glacial moraines. (4.) No erratic blocks with striations.'' (5.) No 

 roches moutonnees. (6.) The "boulder-clays" referred to are deposits laid down by 

 rivers that flowed from active volcanoes during periods of activity. (7.) The deposits 

 at different heights are due to rivers ; for as the land was gradually raised the base- 

 level of erosion would lie deeper and deeper in the rocks, and portions of the older base- 

 levels would be left at various heights. (8.) No valleys with the characteristic form of 

 those due to glacial erosion have yet been described on Ruajiehu. (9.) No glacial valleys 

 have been described in other parts of the North Island. In general the writer sees no 

 reason to dejiart from the view long held by aU New Zealand geologists, that the amount 

 of Pleistocene glaciation in New Zealand did not reach to the magnitude of an ice-sheet. 

 On the western side the ancient glaciers reached the coast in many places in the south 

 of the South Island, while on the eastern side they threaded far through the mountain- 

 valleys towards the coast. 



