Prehistoric North America / by W. J. McGee and Cyrus Thomas.

  • McGee, W J, 1853-1912.
Date:
[1905], ©1905
Catalogue details

Licence: Public Domain Mark

Credit: Prehistoric North America / by W. J. McGee and Cyrus Thomas. Source: Wellcome Collection.

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    under the process of adaptation by developing hardy varie¬ ties, and the selection of new food plants. Another important feature of this northern continent is its mountain systems. One, which is the most important and most extensive, is the great mountain range running nearly parallel with the Pacific coast from Alaska, through the western part of British Columbia, and thence south¬ ward to the Isthmus of Panama, known as the Rocky Mountains north of Mexico, while in the latter republic the name “Sierra Madre” is applied to the chief range. However, the different sections of the great dividing ridge which separates the drainage areas of the two oceans present important differences. In the United States the range expands in width so that in the latitude of Colorado it spreads from Denver to Salt Lake City, forming a broad elevated plateau from four to ten thousand feet in height. This elevated plateau is broken into ridges generally trend¬ ing north and south, with intervening valleys and plains, the chief and, in fact, only well-marked exception to this rule is the Uinta range of Utah and Wyoming. It is usual among the more recent geographers to con¬ sider the whole great mountain region, or Cordilleras col¬ lectively, as a vast elevated plateau which, occupying the greater portion of the width of Mexico from ocean to gulf, enters the United States with a great breadth extending from the eastern face of the Rocky Mountain range west¬ ward nearly to the Pacific coast. Thus considered it includes, besides the chief dividing range, also the Sierra Nevada and its northern continuation, the Cascade range, through the central parts of Oregon and Washington, and thence through British America to high latitudes. The highest points of these ranges are in Colorado and Cali¬ fornia, as Long’s Peak, 14,271 feet; Gray’s Peak, 14,341 feet; Pike’s Peak, 14,108 feet, and others in the former State; and Fisherman Peak, 14,448 feet; Mount Whitney, 14,898 feet, and Mount Shasta, 14,380 feet, in the latter State. Northward in British Columbia the system is not