98 ORIGIN OF LIFE IN AMERICA 



south. If such an event had happened we should not have had 

 such a large percentage of peculiar forms of animal life in 

 Alaska, and more southern forms ought to have found their 

 way there, such as the American deer and many others. 



It would seem, therefore, as if both the Atlantic and the 

 Pacific Ocean became closed in the north simultaneously and 

 remained so for a considerable time (Fig. 7). The southern 

 shores of both the 'great land bridges were then under the direct 

 influence of warm ocean 'currents resulting in favourable con- 

 ditions for the growth of vegetation and the food supply 

 for large mammals. The northern shores of the land 

 bridges, on the other hand, were in immediate contact 

 with a closed Arctic Ocean, whose waters would naturally 

 have remained frozen for the greater part of the year. 

 During winter the snowfall all round the northern Atlantic 

 and northern Pacific Oceans was probably considerable. 

 The land being, moreover, at a higher level, this would 

 have resulted in the production of local glaciers. Marine 

 transgressions from the Arctic Ocean then seem to have 

 taken place across northern Russia, as I described in my; 

 work on the History of the European Fauna,* and across 

 the lowlands of arctic Canada as indicated on pp. 46 49. 

 My views on the Glacial Epoch and its nature are thus at 

 variance with those held by most geologists of the present 

 time. They agree with those put forward by Sir William 

 Dawson,f and are more in accordance with the current 

 opinions at the time when the Glacial Epoch was spoken of 

 as the " Diluvial Age." 



It is very generally believed, as I mentioned before, that the 

 climate in northern Europe and northern North America was 

 very cold, and that all that vast region which is covered by 

 the deposit known as " Glacial drift " had been invaded during 

 the Glacial Epoch by thick masses of land ice, so as to destroy 

 practically all life or drive it far southward of the southern 

 limits of the drift. I stated in another chapter (p. 77) that I 

 did not intend to make a special point in discussing the origin 

 of the Glacial Epoch. I only incidentally bring forward a 



* Scharff, E. F., ''History of European Fauna," p. 172184. 

 t Dawson, W., " Ice Age in Canada." 



