WELLINGTON PHILOSOPHICAL SOCIETY.

New Zealand Times, Volume XXIX, Issue 4183, 17 August 1874, Page 3

WELLINGTON PHILOSOPHICAL SOCIETY.

A meeting of the members of the above Society was held in the Maori House, on Saturday evening, the President (Dr. Knight), in the chair. There was a good attendance. The minutes of the previous meeting wore read and confirmed. NEW MEMBERS. The following gentlemen were announced as having been elected members since the previous meeting ;—Mr. Erederick Bull, and Mr. E. H. Bold, G.E., Napier. BUSINESS. A paper on the alleged Pleistocene Glaciation of New Zealand by Mr. W. T. L. Travers, 8.L.5., was read by the author. This paper occupied the whole evening, and was devoted to the discussion and refutation of the theory, advanced by Dr. Haast in various reports and addresses, that during the pleistocene period the physical condition of these islands resembled that of Greenland, where the country is covered with an ice sheet, and glaciers protrude into the sea and break off to form icebergs. After showing that such a view is inconsistent with the evidence afforded by the existing and extinct fauna and flora of the country, the author argued that the former extension of the glaciers was due to a great elevation of the Islands that followed the close of the Miocene period, to an altitude exceeding its present elevation by fora- or five thousand feet, and that the ensuing retreat of the glaciers was due to subsequent depression, the extent of which exceeded the former maximum elevation, and that in post-pleiocene times there has been a slight re-elevation with a corresponding re-advance of the glaciers in the valleys radiating from the chief mountain centres, such as Mount Cook. The author also controverted Dr. Haast’s view, that the alleged glacial period was due to the peculiar position of New Zealand, lying as it does, at right angles to the equatorial N.W.. and the polar S.E. winds, causing such an accumulation oiniri as to lower the line of perpetual snow ; and argued that no such atmospheric currents could ever exist. The author next criticised Dr. Hector’s suggestion, that, had the interior of Australia been submerged to any considerable extent, the amount of vapor contained in the N.W. wind must have been greater, and the amount of snow condensed from them by the New Zealand Alps, and the resulting glaciers, must have been correspondingly greater than at present; arguing that the winds, which reach New Zealand from the N.W., are return «trades” that have not passed over the surface of the Australian Continent. Eor the same reason he rejected the theory advanced in the President’s address that the hot winds which impinge on the West Coast of New Zealand derive their heat from the surface of traliaMr. Crawford said that, without entering on the subject of glaciation, he must certainly disa'Tce -with the author in his -view that the S.E. trades . prevailed over Australia, and thought that, by his diagram he had stabbed his own argument with a stiletto of chalk. Nodoubt it was right and proper that the S.E. trades should blow over Australia, but unfortunately, as a matter of fact, they did not. They only passed over the N.E. corner, and it was well known that hot dry winds from the N.W. were prevalent along the eastern portions of Australia, at least south of Brisbane. Mr. J. A. Wilson thought the extent of surface in Australia traversed by the, S.E. trades was greater than stated by Mr. Crawford, and gave an interesting sketch of the distances of the rainfall on the different Australian water sheds. He thought the hot N.W. -winds were due to the monsoons, a view which had escaped the notice of the author of the paper. He did not believe the N.W. winds reached New Zealand, and they were certainly never encountered on the ocean surface that intervenes; whether or not they were in the higher regions of the atmosphere could only he determined by a balloon. The hot winds of Canterbury he thought had nothing to do with the Australian hot winds, but were due to the evolution of moisture from winds passing over the Southern Alps. Dr. Hector said the paper just read touched on nearly every branch of the physical geography of New Zealand, and opened a great variety of debatable questions. Mr. Travers considered that Dr. Haast was wrong in the period to which he attributed the glacial conditions, and also in the cause he suggested for them. Agreeing with the author that vague assumptions were unscientific, he had anxiously expected some definition of the meaning that he attached to the terms pleistocene and pliocene, as in that lay the first ground of difference with Dr. Haast. The former word was used by Sir Charles Lyell for certain terrestrial or drift beds that are contemporaneous with newer pliocene ; in fact, an extension back in time, in some localities, of post-tertiary conditions. Owing to its frequent mis-applieation to merely post-pliocene,-strata. Sir Charles recommended that the term should he dropped, but if used in its original and extended sense, he (Dr. Hector) thought it would be useful to retain it, and it seemed to him that it would suit Mr. Travers' view, as he understood him to hold that no great change in the fauna and flora of the Islands had taken jilace since the great glacierperiod. Apart from this verbal consideration he thought the evidence for classifying even our marine tertiary strata did not, except as a matter of convenience, warrant our applying to them terms that have definite meanings in the other hemishere, where the geology has been more fully worked out. With reference to Dr. Haast’s opinions, the report quoted from so largely was neither his first nor his last, and among them were many views in variance with each other. He did not attach much importance to this so long as the facts recorded were right, as speculations on this and kindred subjects were only muffled echoes of discussion in the old country where opinions change like the fashions. The extensive citations just made from Geikie’s work on the “ Great Ice Age ” were a case in point. It, being a new work, was treated as an authority, but he thought that, even in the passages read, there were views that had already been disputed and modified. Leaving the question of whether the glaciers were largest during an extended pleistocene period, or were contemporaneous with pliocene marine deposits elsewhere, which is Mr. Travers’ view, as still open, ho agreed with the author’s idea of the cause of the former great size of the glaciers, though not requiring for his theory such an ’ extreme degree of elevation of the land. He thought there must have been a greater extent of land above the snow line, partly due to increased height, but also due to the more massive form of the mountains before they had been cut up into valleys, ridges, and peaks, but that a third cause may bo found in changes in the physical geography of the surrounding region. The winds had been described as blowing steadily from certain quarters which did not bring them over the Australian continent, but the regular gyration of the winds throughsuooessivo quarters had been quite overlooked. This rotation is performed in from five to seven days, and through its influence largo columns of the atmosphere are transferred from one area to another. Prevalent wind in New Zealand only means that there is a preponderance of wind from a certain quarter, and not a steady wind like the trades. The fact is undoubted that warm winds from the N.W. do impinge on New Zealand, but the only fair way to discuss this subject is by making use of the abundant meteorological data which lias been accumulated. The meeting adjourned at 10.15 p.ra. to Saturday next.