NOTICE OF A MEMOIR ON GLACIERS AND ICEBERGS IN RELATION TO CLIMATE, BY DR. A. J. VON WEICKOFF. (In the Proceedings of the Geological Society of Berlin, 1881.) With remarks by PRINCIPAL DAWSON, F.R.S.

This memoir presents a very clear statement of the physical causes and conditions of the accumulation and distribution of snow and ice in different parts of the world, in illustration of the possibility of the existence of continental glaciation in the Pleistocene age. The following is a free translation of the author's summary of his conclusions, which though sufficiently trite as matters of physical geography, are deserving of repetition at a time when the principles of that science are treated with so great contempt by certain schools of glacialists.

1. The presence of water tends to moderate the extremes of temperature both in place and in time.

2. It does this, both by virtue of its great capacity for heat, and by its cooling and heating powers when passing from the solid into the liquid and gaseous states, and the reverse.

For ex

3. These effects extend widely in place and time. ample, near the south pole, the higher strata of air are warmed by the abundant congelation of vapour into snow, and the snow having fallen and having been changed into the ice of glaciers and icebergs, is in that condition carried far to the north, and hundreds of years after it has fallen as snow, is active in cooling the ocean and the air as far north as the latitude of 40°.

4. The general effect of the changes of condition of water, along with the resulting formation of clouds and mists, is to raise the temperature of winter and to depress that of summer.

5. The currents of the ocean have an especially great influence in the mitigation of the extremes of temperature, the direct effect of which is much greater than that of the winds.

6. The winds appear to act mainly in diffusing the temperature of the ocean currents.

7. Though the winds may be in the first instance the motive power of the main oceanic currents, yet the effects of the distribution of land and of the form of the sea-bottom become paramount in influencing these when once set in motion.

8. At the present time, the distribution of the trade-winds and monsoons is such as to divert a large quantity of warm equatorial water into the northern hemisphere, producing an excess of warmth above that of the S. Hemisphere between latitudes 40° and 59° N.

9. This effect is intensified by the narrowing of the seas to the north, and is of course especially felt on the western sides of the continents.

10. Not only does the Southern Hemisphere thus lose a large share of its warm water, but the effect of the remainder is dissipated by being spread over a vast expanse of sea.

11. This great expanse of ocean in the Southern Hemisphere is favourable to the deposit of snow and formation of glaciers, by furnishing a great evaporating surface, and at the same time a low general temperature facilitating precipitation. This applies to the Antarctic continent, and also permits the formation of glaciers far to the north in New Zealand and in South America.

12. On the other hand the present condition of the Northern Hemisphere is unfavourable to glaciers, because the sea is so warm that deposition near the coasts is rather as rain than snow up to pretty high latitudes, while the continents are so wide that there is little precipitation in their interior.

13. Thus there are no glaciers in Eastern Siberia, even in the mountains, where the mean temperature is only 15° to 16o C., and Central Asia generally is unfavourable to glaciation on account of its dryness, while Eastern Asia is acted on by the monsoons. If, therefore, the extent of land in Asia has not materially changed since the Pliocene period, there could not have been great glaciers there since that period. Even the submergence of the great plain of China could not materially affect this result, though it might cause glaciers in the mountains of Japan.

14. To explain the great Post-pliocene glaciers, of which traces are found in Western Europe, it is necessary to suppose that the temperature was lower, either on account of submergence of the low lands or of diversion of warm currents, or both causes may have operated. A submergence connecting the White and Baltic Seas would greatly promote the production of snow and ice. But this could not affect the interior of Russia or of Asia, so long as their plains remained above water.

15. The submergence of the plains must be a necessary condition of the general glaciation of the higher lands.

16. Astronomical changes do not affect this result. With a great eccentricity of the orbit and the winter in aphelion the colder winters and hotter summers would produce more powerful monsoons, while on the opposite condition the interior of the continents would have warmer winters and cooler summers and In either case the conditions for continental

weaker monsoons.

glaciers would not be improved.

17. These considerations show that general coverings of ice stretching from the Pole to perhaps 45° are impossible. Under conditions of submergence of the plains the sea must keep open, in order to afford material for snow on the remaining high lands, and with large continental plains the climate will be too dry for glaciers. Thus there must always be seas free from ice, or continental plains free of ice, and under most supposable conditions there must be both.

Applying these very simple geographical truths to the North American continent, it is easy to perceive that no amount of refrigeration could produce a Continental glacier, because there could not be sufficient evaporation and precipitation to afford the necessary snow in the interior. The case of Greenland is often referred to, but this is the case of a high mass of cold land with sea mostly open on both sides of it, giving, therefore, the conditions most favourable to precipitation of snow. If Greenland were less elevated, or if there were dry plains around it, the case would be quite different; as Nares has well shown in the case of Grinnel land, which in the immediate vicinity of Greenland presents very different conditions as to glaciation and climate

If the plains were submerged and the Arctic currents allowed free access to the interior of the continent of America, it is conceivable that the mountainous regions remaining out of water should be covered with snow and ice, and there is the best evidence that this actually occurred in the glacial period; but with the plains out of water, there could never have been a suffi. ciency of snow to cause any general glaciation of the interior. We see evidence of this at the present day in the fact that in unusually cold winters the great precipitation of snow takes place south of Canada, leaving the north comparatively bare, while as the temperature becomes milder the area of snow deposit moves further to the north.

The writer of this note has always maintained these conclusions on general geographical grounds, as well as on the evidence

afforded by the Pleistocene deposits of Canada, and he continues to regard the supposed evidence of a terminal moraine of the great Continental glacier as nothing but the southern limit of the ice-drift of a period of submergence. In such a period the southern margin of an ice-laden sea where its floe-ice and bergs grounded, or where its ice was rapidly melted by warmer water, and where consequently its burden of boulders and other debris was deposited, would necessarily present the aspect of a moraine, which by the long continuance of such conditions might assume gigantic dimensions.

In the recent remarkable work on glaciers by Messrs. Shaler and Davis, it is apparently maintained that in North America a continental glacier extended in temperate latitudes from sea to sea, and this glacier must, in many places at least, have exceeded a mile in thickness. Independently of the physical difficulties attending the movement of such a mass without any adequate slope, difficulties with which the authors endeavour to deal, though not very satisfactorily, it is obvious, from the considerations above stated, that the amount of snow necessary to the production of such a glacier could not possibly be obtained. With a depression such as we know to have existed, admitting the Arctic currents along the St. Lawrence Valley, through gaps in the Laurentian watershed, and down the great plains between the Laurentian areas and the Rocky Mountains, we can easily understand the covering of the hills of eastern Canada and New England with ice and snow, and a similar covering of the mountains of the west coast. The sea also in this case might be ice-laden and boulderbearing as far south as 40, while there might still be low islands far to the north, on which vegetation and animals continued to exist. We should thus have the conditions necessary to explain all the anomalies of the glacial deposits. Even the glaciation of high mountains south of the St. Lawrence Valley would then become explicable by the grounding of floe-ice on the tops of these mountains when reefs in the sea. The so-called moraine, traceable from the great Missouri coteau in the west, to the coasts of New Jersey, would thus become the mark of the southern limit of the subsidence, or of the line along which the cold currents bearing ice were abruptly cut off by warm surface

waters.

Whatever difficulties may attend such a supposition, they are small compared with those attendaut on the belief of a continental

REPORT ON THE PETER REDPATH MUSEUM

OF MCGILL UNIVERSITY.

Prepared by PRINCIPAL DAWSON for the first meeting of the Museum Committee, March 11th, 1882.

[In the terms of the gift of the Peter Redpath Museum to the University, it is provided that the immediate management of the Museum shall be entrusted to a 66 Standing Committee of the Corporation, to be called the Museum Committee, to consist of the Principal as Chairman, and three other members of the Corporation, with whom shall be associated the Logan Professor of Geology and the Professors of Mineralogy, Zoology and Botany, and of other departments of Natural History in the Faculties of Arts or Applied Science of McGill College, should there be such Professors. The Committee shall have power to appoint any of its members Honorary Curator or Curators of the Collections or of any part thereof, and to arrange the times at which different Professors and their classes may teach or study in the Museum."

A Museum Committee was accordingly appointed by the Corporation of the University, at its meeting in January, 1882, and consists of the following members: The Principal (ex officio), Peter Redpath, Esq., Hon. Mr. Justice McKay, Dr. G. W. Campbell, Dr. B. J. Harrington (ex officio). The following report was presented by the Principal to the first meeting, with the object of placing on record the steps taken by him up to that time in his capacity of Curator of the Museum, under the regulations of the University.]

The noble Museum, erected for the University by the munificence of Mr. Redpath, has now so far advanced toward completion, that it will probably be ready for the reception of specimens in May next, and it is extremely desirable that the collections to be contained in it shall be in as perfect a condition as possible at the time of the formal opening, which is intended to take place on the 24th of August, on occasion of the meeting of the American Association in Montreal. In view of these dates, it

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