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Show HlO ISLAND LIFE. (PAitT I. country did not consist almost wholly of precipitous snow-clad mountains, it would be capable of supporting most of the vegetable products of the American coast in the latitude of Bordeaux.1 With these astounding facts before us, due wholly to the transference of a portion of the warm currents of the Atlantic to the shores of Europe, even with all the disadvantages of an icy sea to the north-east and ice-covered Greenland to the north-west, how can we doubt the enormously greater effect of such a condition of things as has been shown to have existed during the Tertiary epoch? Instead of one great stream of warm water spreading widely over the North Atlantic and thus losing the greater part of its store , of heat befo're it reaches the Arctic seas, we should have 8everal streams conveying the heat of far more extensive tropical oceans by comparatively narrow inland channels, thus being able to 1 Professor Haughton has made an elaborate calculation of the difference between existing climates and those of Miocene times, for all the places where a Miocene flora has been discovered, by means of the actual range of corresponding species and genera of plants. Although this method is open to the objection that the ranges of plants and animals are not determined by temperature only, yet the results may be approximately correct, and are very interesting. The following table which summarizes tbese results is taken from his LectU?·es on Physical Geogmphy (p. 344) :- Latitude. P'"'"' I M;ooono Difference. Temperature. Temperature. ----- 1. Switzerland . 47°.00 53°.6 F. 69°.8 F. 16°.2 F. 2. Dantzig 54°.21 45°.7 " 62°.6 , 16°.9 " 3. Iceland 65°.30 35°.6 " 48°.2 " 12°. G , 4. Mackenzie Hiver G5°.00 19°.4 " 48°.2 " 28°.8 " 5. Disco (Greenland) 70°.00 19°.6 " 55°.6 " 36°.0 , 6. Spitzbergen . . . 78°.00 16°.5 " 51°.8 " 35°.3 ,, 7. Grinnell Land 81°.44 1°.7 " 42°.3 " 44°.0 , It is interesting to note that Iceland, which is now exposed to the full influence of the Gulf Stream, was only 12°'6 F. warmer in Miocene times, while Mackenzie Hiver, now totally removed from its influence, was 28° warmer. This, as well as the greater increase o£ temperature as we go northward and the polar area becomes more limited, is quite in accordance with the view of the causes which bronght about. the Miocene climate which is here advocated. · CIIAr. JX.] MILD ARCTIC CLIMATES. 1 !)1 transfer a large proportion of their heat into the northern and ~rctic seas. . The .heat t~1at they gave out during the passage, mstead of bemg w1dely d1spersed by winds and much of it lost in the higher atmosphere, would directly ameliorate the climate of the continents they passed through, and prevent all accumulation of snow except on the loftiest mountains. The formation of ice in the Arctic seas would then be impossible; and the mild winter climate of the latitude of North Carolina which by the Gulf Stream is transferred 20° northwards to our islands might certainly, under the favourable conditions which prevailed during the Cretaceous, Eocene, and Miocene periods, have been carried another 20° north to Greenland and Spitzbergen; and this would bring about exactly the climate indicated by the fossil Arctic vegetation. For it must be remembered that the Arctic summers are, even now, really hotter than ours, and if the winter's cold were abolished and all ice-accumulation prevented, the high northern lands would be able to support a far more luxuriant summer vegetation than is possible in our unequal and cloudy climate. 1 Effect of High ExcentTicity on the warm Pola1· Olirnates.If the explanation of the cause of the glacial epoch given in the last chapter is a correct one, it will, I believe, follow that changes in the amount of excentricity will produce no 1 The objection has been made, that the long polar night would of itself be fatal to the existence of such a luxuriant vegetation as we know to have existed as far as 80° N. Lat., and that there must have been some alteration of the position of the pole, or diminution of the obliquity of the ecliptic, to permit such plants as magnolias and large--leaved maples to flourish. But there appears to be really no valid grounds for such an objection. Not only are numbers of Alpine and Arctic evergreens deeply buried in the snow for many months without injury, but a variety o£ tropical and sub-tropical plants are preserved in tbe hot-houses of St. Petersburg and other northern cities, which are closely matted during winter, and are :thus exposed to as much darkness as the night o£ the Arctic regions. We have besides no proof that any of the Arctic trees or large shrubs were evergreens, and the darkness would certainly not be prejudicial to deciduous plants. With a suitable temperature there is nothing to prevent a luxuriant vegetation up to the pole, and the long continued day is known to be highly favourable to the development of foliage, which in the same species is larger and better developed inN orway than in the south o£ England. |