GEOLOGICAL SEASONS. 199 



accessible as Alaska ; a new continental connection may 

 stretch across the South Pacific. On the other hand, the 

 American Arctic archipelago may become submerged; the 

 sea may cover the larger part of British America and 

 Siberia, and the civilization which for four thousand years 

 has distinguished the northern hemisphere may be trans- 

 ferred to the southern. 



Another outcome of this cosmical theory of terrestrial 

 glaciation possesses, at least, a scientific interest. As the 

 periods of high eccentricity must continue from 50,000 

 to 75,000 years, the coincidence of the winter solstice with 

 the aphelion must occur at two or three epochs during a 

 term of high eccentricity; and these epochs would alter- 

 nate with coincidences between winter solstice and peri- 

 helion. That is, two or three epochs of intense glaciation 

 must occur during one term of high eccentricity, separated 

 by interglacial epochs of milder temperature. Phenomena 

 precisely answering to this deduction are believed to pre- 

 sent themselves in connection with the deposits of the 

 Glacial Period of geology. To say no more, geologists 

 now generally recognize at least one interglacial period 

 during the progress of the 'last great ice-age. 



