The Cause oi the Glacial Epochs. than three millions of years. Five hundred and twenty three thousand three hundred years ag the poles of the earth lay in the plane of the ecliptic. Then each pole dur ness for more than three months and in summer to thirty days (720 hours) of almost perpendicular sunshine. Daring such epochs as that tropical vegetation would grow right at the poles and animals accordinglywould feed and dwell there. Broad and thick sheets of ice would accumulate an nually and cover nearly a whole hemisphere at a time al though but thin around their edges. And the speedy thaw
The Cause oi the Glacial Epochs. than three millions of years. Five hundred and twenty three thousand three hundred years ag the poles of the earth lay in the plane of the ecliptic. Then each pole dur ness for more than three months and in summer to thirty days (720 hours) of almost perpendicular sunshine. Daring such epochs as that tropical vegetation would grow right at the poles and animals accordinglywould feed and dwell there. Broad and thick sheets of ice would accumulate an nually and cover nearly a whole hemisphere at a time al though but thin around their edges. And the speedy thaw coming epoch. In about 184800 years from now the equator of the earth will again lie in the plane of the ecliptic. That will be the middle of one of the greatest glacial epochs which come to our earth. It comes on and goes off gradually of course and therefore it will begin some fifty or sixty thousand years before that and be gone in another fifty or sixty thou sand years. Then will be the time when the vast circular fields of ice grow in thickness to perhaps several miles especially at and 000 years and conceive of its thickness. Think of the at tractive force of the sun drawing such huge fields outwardly ward tendency all the time ; and see how it becomes possible down on the top of another lying in its path. It was doubtless during the latest one of the kind (that is some thing near 1231000 years ago) that the crest of a certain names just now but the fact is well known to geologists. These are the periods which as it were turn animal and clination of the earth to the sun causes all her climatic changes ; and thus creatures and vegetation foreign to cer tain localities now will be found in others than they are now in in the far future as has been the case many times In the past ; for the earth has seen several glacial cycles and her animal and vegetable genera may truly be called wandering restless and ever shifting thingsfor neither in dividually has any permanent abiding pl
Size: 3316px × 4728px
Location:
Photo credit: © Corantos / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: 720, 184800, accordinglywould, accumulate, ag, al, animals, broad, coming, cover, daring, days, dur, dwell, earth, ecliptic, edges, epoch, epochs, equator, feed, glacial, gradually, greatest, grow, hemisphere, hours, ice, lay, lie, middle, millions, months, ness, nually, oi, perpendicular, plane, pole, poles, sheets, speedy, summer, sunshine, thaw, thick, thin, thousand, time, tropical, twenty, vegetation, years
