Page:The Journal of geology (IA journalofgeology21894univers).pdf/50

This page has been proofread, but needs to be validated.
36
THE JOURNAL OF GEOLOGY.

the slope of the Sierra is—in the mining region at least—quite moderate, for if we allow a rise of 7,000 feet from the lower edge of the foothills to the crest of the range, the distance between the two points being about seventy miles, the average rise is only 100 feet to the mile, which gives an angle of slope of less than two degrees. And if one ascends the Sierra, keeping on the divide between any two rivers in the mining districts, he will find himself, for most of the time at least, on what seems to be a plain with a very gentle rise. Let the traveler, however, turn and attempt to make his way across the country, in a line parallel with the crest of the range, and he will discover that this apparent plain is cut into by the gorges or cañons in which the present rivers run, in a most extraordinary manner; he will find it several hours' work to descend into one of these and rise again to the general level on the other side, even if assisted by a well-beaten trail. All along the western slope of the Sierra the streams have worn for themselves deep cañons, and it is these tremendous gorges which form the leading feature of the topography of the region. If the streams ran nearly on a level with the general elevation of the surface, the whole character of the mountain slope would be changed. This was formerly the condition of the drainage of the Sierra slope."[1] Concerning the topography of the same region, Mr. Ross E. Browne remarks that "at certain favorably located points an extended view is obtained of the Forest Hill and neighboring divides. Upon losing the effect of the detail, one receives the impression of a general uniformity in the grades of the summit-lines. These summit-lines appear as the remaining traces of a gently undulating plain, sloping regularly from the bases of the massive peaks of the Sierra to the Sacramento valley."[2] Extended views of the western slope of the Sierra Nevada may be obtained at many points from the Central Pacific railroad between Colfax and the summit, and they fully illustrate the feature referred to.

  1. ↑ Auriferous Gravels of the Sierra Nevada of California, by J. D. Whitney.Pp. 63-64.
  2. ↑ The Ancient River Beds of the Forest Hill Divide.Tenth Annual Report of the State Mineralogist of California, 1890, p. 435.
This article is issued from Wikisource. The text is available under Creative Commons Attribution-Share Alike 4.0 unless otherwise noted. Additional terms may apply for the media files.