History of Nevada; . ong these lines of elevation volcanoesbroke out and sent floods of lava, the future propylites,trachj-tes, and other forms of rocks, other than theordinary stratified rocks, associated with the min-eral veins. With the elevation of the mountainranges came denudation of the upper portions, and adeposit of tertiary matter in the retreating portions of these folded strata were so fardown into the earth as to become, or rather remain,subject to a heat well known to increase on anaverage one degree for each fifty feet, reaching per-haps a higher than the boiling point
History of Nevada; . ong these lines of elevation volcanoesbroke out and sent floods of lava, the future propylites,trachj-tes, and other forms of rocks, other than theordinary stratified rocks, associated with the min-eral veins. With the elevation of the mountainranges came denudation of the upper portions, and adeposit of tertiary matter in the retreating portions of these folded strata were so fardown into the earth as to become, or rather remain,subject to a heat well known to increase on anaverage one degree for each fifty feet, reaching per-haps a higher than the boiling point, while theupper portions were exposed to the lower tempera-ture of the surface of the earth. The rents and fissures, as well as the openings of naturalcleavage, would also be permeated by the heatedwaters circulating through these fissures, all ofwhich would hold more or less minerals in we could have seen an east and west section ofNevada, it would have presented something of thefollowing appearance:—. Though the illustration is imperfect, as some ofthe axes of elevation, like Mount Davidson, by thistime were several thousand feet above the surround-ing country, and the strata of trachytes, propylites,and other igneous rocks have become highly inclined,following down the slopes of the newly-formed andperhaps still rising mountains, the portions sur-mounting the axes of elevation having been denudedaccording to the second diagram in this the upheaval or folding of the strata the dif-ferent rocks would have had about the following po-sition with respect to each other:— Tnclyle. Syenite, E UR Graaiuc Mt- Authorities differ as to tlic plane of elevation at thetime of the deposit. Baron Hichthofen, ClarenceKing and Hossiter \V. ilaymond, were inclined togive quite an inclination to the slopes at the time ofthe outpour of proi>ylito and trachyte. John , a later authoritj-, fixes the plane nearer ahorizontal. If Mount Davidson is the axis of
Size: 2918px × 856px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1880, bookidhistoryofnev, bookyear1881
