Reports of Explorations and Surveys to Ascertain the Most Practicable and Economical Route for a Railroad from the Mississipi River to the Pacific Ocean Volume 7

Reports of Explorations and Surveys to Ascertain the Most Practicable and Economical Route for a Railroad from the Mississipi River to the Pacific Ocean Volume 7

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This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1857 edition. Excerpt: ...mountains; the stream taking the advantage of the chasm between the plutonic axis and the elevated strata on its southern side. The upheaving mass on the north side of the river is variously c0mposed----thus, commencing at the water's edge and ascending the right bank of the river: C 1st. Hornblende porphyry, (felspar and hornblende, in crystals.) 2d. Basalt. 3d. Hornblende porphyry; crystals of hornblende, large.. 4th. Amygdaloidal trachyte; a brownish felspar rock. 5th. Felspar in dykes, walled by 6th. Trachyte. ' The basaltic dyke has a thickness varying from 15 to 20 feet, and rapidly merging into the hornblende porphyry on either side. The felspar dyke has a greater breadth and does not merge into the trachytic amygdaloid, with which it is in contact. This intrusive mass of varied plutonic character is itself a foreign body, thrust through the granitic basis which here and there (though not appearing in the immediate locality) shows itself. In its elevation it has carried up with it two beds of stratified sandstone and a capping of basalt and purplish trachytic amygdaloidal felspar. The latter is a layer about six feet in thickness, and underlies the basalt, which is about 15 feet thick. The great mass of stratified rock is a yellow sandstone conglomerate, which dips away from the central mass at an angle of 15, and generally toward the east; but at this point there is no uniform dip over any extent of ground. South of this point a few hundred yards is a canon in the bed of a creek, emptying itself lower down into the Gila, where the sandstone is better displayed and slopes gently, with a dip 12 east; it is here yellow conglomerate, about 60 feet thick; the pebbles being granitic and volcanic. It was up this creek the trail led to...show more

Product details

  • Paperback | 202 pages
  • 189 x 246 x 11mm | 372g
  • Rarebooksclub.com
  • United States
  • English
  • black & white illustrations
  • 1236878442
  • 9781236878441