The ice age in North America and its bearing upon the antiquity of man5th edwith many new maps and illus., enland rewritten to incorporate the facts that bring it up to date, with chapters on Lake Agassiz and the Probable cause of glaciation . er that Turns, to the South Sas-katchewan. Mr. Upham writes me that he has followed thisold valley for one hundred and twenty-five miles as far asBirtle, in Manitoba. According to Professor Hind, thelength of the valley of the QuAppelle, fi-om Birtle up tothe Saskatchewan, is two hundred and sixty-eight miles indirection northwest by southeast. The valle
The ice age in North America and its bearing upon the antiquity of man5th edwith many new maps and illus., enland rewritten to incorporate the facts that bring it up to date, with chapters on Lake Agassiz and the Probable cause of glaciation . er that Turns, to the South Sas-katchewan. Mr. Upham writes me that he has followed thisold valley for one hundred and twenty-five miles as far asBirtle, in Manitoba. According to Professor Hind, thelength of the valley of the QuAppelle, fi-om Birtle up tothe Saskatchewan, is two hundred and sixty-eight miles indirection northwest by southeast. The valley is uniformlyabout one mile wide, and from one hundred and ten to threehundred and fifty feet below the general level, and eighty-five feet above the present level of the South Saskatchewan,the descent being four hundred and forty feet from theSaskatchewan to the Assiniboin. The inclosing bluffs con-sist mainly of till, and the whole trough is characterized bynumerous long, shallow lakes. These lines of marginal drain-age are readily explained upon the glacial hypothesis heremaintained, and are a strong proof of that hypothesis. As theice receded, more northern outlets were opened, and thesetemporary channels were natuialiy Fig. 100—Map of South Dakota showing the extent to which the channel of the MissouriRiver was permanently changed during the early Wisconsin epoch. The broken 1 InesIndicate thefornier course of the Grand, Cheyenne, and White Rivers as they joinedthe original Missouri when flowing through the James River valley. (Map by Todd.) 336 THE ICE AGE JJV NORTH AMERICA. According to Professor Todd the preglacial MissouriRiver entered the valley of the James near its upper portion,reaching its present channel at Yankton. Having filled thisvalley, the advancing ice from the northeast obstructed themouths of the Grand, Moreau, Cheyenne, and White riverand, forcing the drainage in front of the ice across the colsbetween these streams, gave rise to the pres
Size: 1966px × 1271px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthoruphamwarren18501934, bookcentury1900, bookdecade1910
