ANNIVERSARY ADDRESS OF THE PRESIDENT. XXXV 



former absence of glaciers, during our glacial period, in a region now 

 so much colder than Europe, appears at first sight a great anomaly. 

 It presents, however, no real difficulty, because those very causes 

 which I believe to have produced the glacial cold of Europe would 

 necessarily diminish the cold of northern Asia, and more especially 

 that portion of it immediately east of the Ural chain, as I have ex- 

 plained in my paper " On the Causes of Changes of Terrestrial Tem- 

 perature/' This effect would be due to the extension of the Atlantic 

 Ocean to the eastward, so that the region of the Ural would become 

 part of the western shores of the old continent, and would experience 

 climatal influences similar, though far less in degree, to those now 

 experienced in our own region. Hence what I have termed the line 

 of 32° F. would be higher in north-western Asia than at present. 

 On the other hand, the extension of the ocean to the eastward would 

 lessen the great difference which now exists in northern Asia between 

 the summer and winter temperatures ; and on this account the height 

 of the snow-line above the line of 32° would be diminished. Conse- 

 quently the absolute height of the snow-line would be increased by 

 the first cause and diminished by the second, and would probably be 

 not very different from its present height, though it might possibly be 

 somewhat less. Now, since the configuration of the mountains was 

 probably very nearly the same at the glacial epoch as now, the ex- 

 istence of glaciers upon them would depend upon the height of the 

 snow-line ; and, that height not being materially altered, there is no 

 more reason why glaciers should have existed there at the more 

 remote than at the present epoch; and at present we know that 

 there are none in the Ural chain as far as the 70th degree of lati- 

 tude*, and none on the mountains of northern Asia descending nearly 

 low enough to reach the level of the shallow sea, which we suppose 

 to have covered the low lands of that region during the glacial period. 



This former absence of glaciers, and the comparative repose of 

 northern Asia during our glacial epoch are sufficient to account for 

 what appears at first sight extremely anomalous — the fact, that while 

 on the west of the Ural Mountains we have a district covered with 

 enormous erratic blocks, there is scarcely a single block to be found 

 on the east of that chain at any distance from its original site, the 

 whole mass of detrital matter, too, being very small and principally 

 referable to merely local causes. 



I cannot quit this part of our subject without reminding you of 

 the lucid manner in which the authors of the ' Geology of Russia ' 

 have pointed out how well the above state of northern Asia accords 

 with the supposed existence of Mammoths during the glacial epoch, 

 and how happily Sir Charles Lyell and Professor Owen explained 

 the capabilities of those animals to sustain the hardships of a cold 

 climate. But before the publication of Dove's map of isothermal 

 lines, we had no adequate means of accurately estimating the effect 

 of such conditions as those above assumed on the climate of north- 

 western Asia. The extension of the Atlantic Ocean nearly to the 

 foot of the Ural chain would heighten considerably the mean annual 

 * Geology of Russia. 



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