OTAGO INSTITUTE.

Otago Witness, Volume 06, Issue 2899, 6 October 1909, Page 17

OTAGO INSTITUTE.

THE GLACIATION CONTROVERSY.

MEETING TERMINATES BY

EXHAUSTION.

I A special meeting of the Otago Institute was held on Wednesday, 22nd inst., in the Museum room, to allow oi a continuance of the reading of the papers prepared upon this subject' by ■ Professors .Park and Marshall ' and Mt G. M. Thomson and Dx Benham. ' Professor Park opened by dealing at some length with some of the arguments , used oy Professor Marshall in his first paper, and to which he had read a reply at the previous meeting. The first point | was with reference to the map which Pro- . fessor Marshall had exhibited showing the stream ramifications of the Nightcaps district, the argument being that streams ran in accord with the rock formation, and the spread of the stream showed that no level- : ling- of the land by a glacier had taken ' place. Professor Park, in reply, said that this map was valueless, save with the specification of contours, and to illustrate his point, he showed a model of a section of the land near Waihola, in which stream ramification'} wece apparent .flowing over a comparatively ' flat surface, this being, he said, an instance of how streams became impressed on land of glacial origin. Referring to the y Greenstone glacier, ho repeated his contention that, even' leaving out the question of the east coast, in the meantime there' had been a vast continuous ice-sh-set occupying the whole 4 interior of Otago, and consequently filling every valley therein.' Following on from this, after giving a general review" of the matter, he proceeded, in accordance with the promise contained in his first paper to give " abundant evidence of glacial erosion" under various forme. A closo scrutiny of the topographical features of the eastern portions of Southland, Otago, end Canterbury disclosed evidence that the present configuration of the country had been moulded by ice erosion. The professor then referred to gleciation evidence in the Wakatipu and coastal districts— which had been already dealt with in our reports of both the presidential paper of the institute and in our report of last week's meeting, appearing in Saturday's issue, — and then proceeded to cite specific instances where there were deposits of fluvio-glacial drift resting on a micaschist floor. A lengt'ry and detailed examination .of the Taieri moraine was then entered upon, the contention 'being that this stretched from Allanton to some 25 or 30, miles southward, and was composed r* an upper and a lower series, the whole mass being partially consolidated into a breccia-conglomerate. This glacial deposit varied from 0 to 1100 feet in thickness. After this examination, he submitted that the Taieri moraine, in view of its extent, was a ground moraine of an ice sheet, and not a terminal moraine of a local glacier. Detailed reference was then made to the configuration of the land in North Otago. having special reference to the Waitaki glacier, the hills near which showed a thick deposit of yellowish browm clay or loess. Evidence was also adduced fiom Canterbury and Wellington. Further, iii compliance with the promise of the first paper, the professor then dealt with the assertion of Profesor Marshall, that the clays of the Oam«.ru and Timaru districts were not of a sclaeial origin, but loess. I Admitting that there was a difference of opinion amongst authorities upon the formation of 6<iil of this character, the t>rofessor said that the accumulations of loess here doubtless owed their origin chiefly to the flood waters escaping from the margins of the old land ice. Quoting next th« opinion of Agassiz, that the Southern Hemisphere had passed through a great ice age, in all respects parallel with thab in the Northern Hemisphere, the professor ask«vd if the Southern Hemisphere had been subjected to this, as was -Droved* to be the ciibo by facts from South America, .how was it possible that New Zealand should have escaped. Attention was also given ti th.9 degree of ice slope, the speaker amplifying in this connection the arguments used on. Tueslay week. In regard to tho possibility of ice from the Antarctic travelling to Now Zealand in a continuous ioe sheet, which was denied by Professor Marshall, Professor Park quoted Captain Scott, of the Discovery Expedition, as having said that he had come to the conclusion that the greater part of tha southern ice sheet was still Afloat and that 'the sea. ran beneath it for hundred! of mika. That beia? so why could not the ice have extended over the 1300 miles to New Zealand did the proper refrigeration conditions obttjp-

j Drawing to a close, the Professor dea?' : seriatim with the, -five criteria of the existi ence of an ice sheet advanced by Professor Marshall in his paper. The first was that to establish an sheet it was necessary to prove the existence of a nearly continuous line of morainic deposits. He (the speaker), however,- said that this did not obtain in England, which was admitted to have been glaciated. Even "in New Zealand, however, 'there was the .Taieri moraine as proofc^The second criteria advanced was that requiring the occurrence of boulder clay over almost the whole area occupied by the ice sheet- Here again, however, this failed, as this did not obtain in England or Scotland, for the glacial drift was very irregularly distributed. The third criteria was that domed hills should exist over the glaciated area. (These did exist in Otago, from the Kakanui down 'to Waikouaiti and from near Dunedin to the Clutha. The fourth point was the existence of -'grooved or ice-worn surfaces of rook throughout the district. These he had shown to abound on every hand. Tie fifth point made was the necessary exiltence of erratics ' r due to glaciation. Prfofessor Park quoted opinions from SirArchibald Geikie and Professor Salisbury, to show that rocks in boulder clay weta ' frequently of local origin. He admitted that a large proportion of the rocks in the , Taieri moraine were local, and had been carried from the west side of the basin, ' bu£ the absence of these foreign rocks had ! not .been ..sufficient to convince Hector'^ , M'Kay, or Hutton of the non-glacial origin of the moraine. No rocks foreign to New Zealand had yet been found in the- coastal' area, nor was it likely. that they would bo found, as the pressure of the central ice sheet bad been away from the land. ' A further recapitulation of some, pi the points brought a very long discourse to a close, under pressure from the chairman. Mr G. M. Thomson advanced several reasons from the botanical j>oint of view against the theory that a glacial epoch: prevailed in pleistocene times in New Zealand, and that what now constituted the South Island (which, according to Professor Park, was only separated' during that epoch) was then covered with an ice-sheet. First, ihe said, the flora of New Zealand contained (according to Cheeseman) 332 genera an<j 1415 species of flowering plants. Of thu number, two genera (Stilbocarpa and Pleurophyllum) and 45 epsciee ace peculiar

bo the Antarctic Islands (Macquarie, Campbell, Auckland, Antipodes Islands and the Snares); while 26 genera and 452 species ate found in the South UUnd «nd Stewart Island, but do not range in the North I«Und. These peculiar South Island forme included such aberrant type* as. Ranunculus Lyallii, the whip-cord Veronicas, the Vegetable sheep (Baoolia. exiraia and mammiDari*), the remarkable woolly Haastias, and many other -singular plants. They formed one of tbe meet interesting oollec- : tk>n* to be found in any part of tho world. He argued that the extraordinary diversity of form and type which prevailed among these genera and species required a very considerable period of time for its development, and that the differentiation probably dated from an era much antecedent to the Pleistocene. Secondly, he said one of the effects of recent glaciation in the Northern Hemisphere wae to. produce among the woody plants, a deciduous type; such plants only, unless specially modified for the purpose, being able to resist the destructive effects of snow. Taking Britain ac an example of an area glaciated within recent geological times, he found that of the 12%5 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 tho emaH-leaved or hard-leaved species, such as Scotch fir, juniper, yew, heaths, goree, etc., which were not -injured by enow. The only soft-leaved evergreen in Britain was the ivy, which did not take hurt with enow. 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 rpp roach of winter, and so being vninjured by snow. In New Zealand, out «>f tho 1415 species of flowering plants, 450 (or 31.8 per cent.) were trees or shrubs. «"'f this number 393 (88.3 per cent.) were • vergreon, 45 (10.1- per oent.) we leafless, while only two species of fuschia were absolutely, and five other plants partially, decidous, -that was, at the outside, less than 1 5 per cent, were fitted to withstand the destructive effects of snow. In the face ot ihese facts, it was impossible to conceive that this island had a general glacial epoch within recent tiroes. Thirdly, there exited in New Zealand, and especially in the South Island, what was called a xerophytic, or desert flora: a group of plants specially modified to withstand drought. These were principally found on the mountain slopes and on the plains on the eastern side of the main ranore ot mountain* formirar the backbone of the South Island. The speaker showed th« effects of this range on the moisture-laden winds which strike the West Coast, causing precipitation of their moisture on the west eide, and great dryness. on the east. He a'so gave examples of the email amount of moisture which the desert plants lost by evaporation, and stated th«,r, roughly i-peakrimj, about 220 species- of floweringr/ants found in the inland parts of the 5 -land belong to this category. Ho arg-aed i.-.at *uch a flora could not have arisen since J :e pleistocene epoch, bu«c that it was prob.ib!y due to an intensification of the I :<?scnt conditions. An elevation of 5000 ft o: the central chain of the South Island comparatively recen* times would have been aeeonvpanied on its eastern side ny an extremely dry climate tending to t.:e production and survival of a xerojMiytic flora. It would also serve to account. 2 or the glacial phenomena bow vi6ib!e in jnanv parts of the country, for the forma\Wt Coast sounds with their terminal t.on of the great glacier lakee and of the iroraines under the sea outside their entrar.cas. Summing up all the evid«iico n\ailable from a consideration of the existing flora of New Zealand, he pronounced ezrongly against the possibility of a glacial epoch within recent geological times. Dr Benham, treating the matter from a biological point of \iew, said that the quehtion of a pleistocene ice sheet covering New Zealand and coHtinuing with the extension of the Polar ice sheet was one that had very important bearings in the character of ■the fauna of these islands; and any geological evidence there might be which seemed to indicate the existence of such an ice sheet must be co-related with biological evidence. In tbe cas© of the Northern Hemisphere the advance of the ice sheet forced existing life to emigrate to the south, whence ifc returned on its withdrawal. But here in tbe south there was no possibility of restocking the land after having been covered by the ice sheet. The fauna of New Zealand was in many respects of a remarkable character owing to tho great specialisation of its members ; yet it contained descendants of ancestors which entered New Zealand at various periods from the north, by way of Now Guinea and other lands. Thus it was seen that at two periods -New Zealand was of much greater extent than at pre*ent — indeed, formed a small continent, embracing New Caledonia, Kermadecs, Chatham Klands, and ihp sub- ' Antarctic islands, though not necessarily at tbe same period. In the continental area

! the descendants of the immigrants became socialised, and since the last period • (pliocene at latest) there bad been no com- ', raunication with any land Or place. They j. knew approximately the date of separation! of New Zealand from other land surfaces — ! in- the latter part of the menzoic, period, — j when it Received many of its invertebrates, probably in ' the carry pliocene,' when" it - extended so far fouth as tn Include the I Campbell. Auckland. and- Macquarie i I Islands-, • -and received its southern forms! ' from America, by way of on Antarctic con- j tineut. It appeared that Cook Strait was formed m. the later pliocene; hence, th^ fauna of the South Island had ever since that period been isolated from that of the North Island. A mere examination of the difference iiir the fauna of the two islands — ' qui*|3 apart from geological evidence — j would indicate that the separation had ; been longer than the pleistocene, for a ■ considerabla period of time was necessary f for the evolution of species. Taking as an J analogy- Britain, which retained its land ! connection with Europe till, after the ice j age, they said that in Britain the species ] wore practically all identical with those of i Europe, but in New Zealand many of the j birds we're represeuted by distinct speciea i ; in the North and South Islands, as, for , ' icistancc, the Maori hen, which had one specips in the North Island and three in the South Island; the nitorium, which had one species in .each island ; the moas, which > existed up to histoiic times, had four dif- ' forent species, and even genera, in the , two islands; and the parrakeet, crow, thrush, robin, tomtit, and \\«ka each had distinct species in each island. As regarded snails, slugs, and other invertebrates, the same was the case, though they ; lacked sufficient detailed knowledge to allow o£ statistics being presented. ; These differences imily a separation. ' ' But if tho South Island wero covered by an ico fheet when the northern limit extended to Cook Strait (vide Bull, p. 40) all the animals of tho South Island must have been wiped out. Whence did the present fauna then arrive? Birds, it will be said, can fly over Cook Strait. True; but there will have been insufficient time for the differentiation of species. But such an explanation is impossible in the case of the snails or silk worm*., spiders or flinhtless insects such as the weta — these all required land connection. The earth worm of the South Island could not have bf«n der'wd from thesp of the North Inland. Perhaps Protestor Park would r»ply that the ice shpet left part of Marl- 1 borough uncovered — but even if it did the co!d would have be«n so intense that ro animals could have survived; and even if Co.->k Si-rait wp-re as v-efc in cx-stenco. we still lackod sufficient tim<* for the c'ifT<TPntiation of species in the two island*. Moreover, the f<en'»ra of earth worms wore so greatly different that much longer time wae necessary. But a still more serious difficulty was incurred when thf>y boro in mind that this pleistocene ice sh^eet " was an extension of the Polar ice shoot " (p. 43). This Polar ice sheet. must have covered Camnbell and Auckland Island* — as ho himself believed to have been the case — for at this time the elevations of the , land in early pliocene placed these islands • in connection with the South Island of New Zealand. This ice sheet must have destroyed all animals and all plants in these islands — aji<l since they had not beon in connection with ajiy land -^uiface since ihp nleistocene, it was impossible for them to have beon peopled sincp that date. Moreover, the soecies of land birds on the Auckland Islands were distinct fiom tho^e of New Z-»alflnd — it. was not a ouestion im»relv of thoir annual flipbt after the ' withdrawal of the ice "fleet That, was quite possible, for several inrroducpd bird" were observed, but the diffe-.-entiation of Sf.o<-ie<! in thr«^ outlying islands was erent, and all indicated a lone separation; while the presence of the flightless duck. a [ centis found nowhere w--s even more i i:riT)re I ; < ;ive. As a result of the recent ex- .' pedition they found from an examination of the various groups of invertebrate that, i although there were simil-irities to them in New Zealand, many of thorn were more nearly allied to South American forms. which could net 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 rf such existing terrestrial forms, which could neither fly nor swim, which could not survive a spa-bath, by tJieir mia rations along a land area extending across the Antarctic region from South America to these islands. It seemed to him that the onus lay with Professor Park to show how , these sub-antarctic islands became peopled. • after their fauna and flora had been wined j out by the pleistocene "ic© sheet. The , whole biological evidence seemed to be en1 tirely antagonistic to his theory. " MoreI over," he said in conclusion. " I believe ' I that the thesis can be strongly supported : , j That there has been no general reduction •of temperature over tho whole Southern \ ' Hemisphere at or about that period." j 1 It vms getting very late when Professor 1 Marshall rose- to veplv, but ac it was the ' wish of the meeting that the- matter should

be proceeded with in preference to having another adjourned meeting, he commnoed, though with reluctance, ac he said he foresaw that he would not be "able to go fully infce the matter. Professor Park's reply to his paper, he said, had taken two and tbree-<tnftffter hours, .and he could not Le expected to deal with that in & few minutes. Ho first of all regretted that there had been a • v<sxy great misrepreßenta-tioQ at the outset, for it was said that he was looking for one phase of glaciation. H* was not looting for any one phase ; he was loking for evidence of any giaciation,. whatever phase it was. In Europe and America they had had six phases of glaciation. New Zealand was evidently to be. allowed only two, but he was not looking for only valley glaciation, as had been Baid, but evidence of any and every kind of glaciation. With reference to th& moraine at Henley, Professor Park claimed that this was a ground moraine of stratified boulder clay 700 ft thick. But the greatest thickness of boulder clay ever previously known was. 50Cft that was not stratified. The stratification there was due to the action of water which could not have been beneath the glacier, because the pressure would drive it out. He believed that with proper climatic conditions a sufficiency of snow and ice would accumulate there to form another glacier, the termination' of which would be pretty much in the same place. With regard to the extent of the moraine claimed by Professor Park — about 25 miles long,— this wae not all morainic material. That great area cf which he talked was really composed of valley tray which had been spread there by river action. There were bigger moraines in New Zaaland than the. one at the Taieri, and these showed the same construction. Exaggeration cf this kind he thought was very unsatisfactory. Then Professor Park had accused him of very dense and crass ignorance in regard io glaciation. And this before an audience in which were two members of the University Council ! Why, he almost expected to be dismissed ! It* was hardly fair, he thought, for one man who represented another department in a University to accuse another man of erro-^ ignorance in his cwn department. Pro.'o^ar Park's vi<ni» on geology had changed in the past. He had written three bulletins on lands in Otago. and yet. two of ihese had contained nr> reference to glaciation. Surely ie was a very sudden conversion, and, like ail sudden converts, Professor Park ha<« rushod to an extreme, but, again, like similar '-onveriicns, would come b-><"-k to the nii-ri a^ain. Thf> Professor fTian repeated his views as to the evidence of glaciation inthe Souther-: Islands. ar,d also in regard to oratie*. Tn regard to the slope of jcs question, Professor Park has Taken ci average of 50ft for thp s'.oiv* in Greenland ; but he (th© sjx-aker) had taken a higher average of 300fr, for which he had given his reasons, tor the Wakatmu Glacier. As a matter of actual fact, the a\<?raere of the Greenland ice elope per mile was 130 ft. The time when this stape was reached was just before 11.30, and the audience had dwindled very seriously, numbering then about a dozen. To do himse.f justice Professor Marshall saw no prospect of ccncludino- for a considerable time. Dr Fulton (chairman) good-naturedly throaienrd he would conclude without him in the chair. Professor Marshall said he would leave with him. Someone suggested that the chairman be asked to leave the chair, and by mutual consent the meeting dissolved. Professor Park waiving his right to a reply to the papers of Mr Thomson and Dr Bonham. So far as the institute is concerned the eontioversy seems to have about come to a conclusion.