Published online by Cambridge University Press: 01 May 2009
If, in the growth of the American continent, the moulding of the land features had not largely depended upon its projection above the sea, favouring or retarding the action of rains and rivers, in sculpturing its surface, there would be little interest as to what was its relative height, before the commencement of the Pleistocene period. But we find valleys vastly greater than meteoric agents could have produced under existing circumstances. Thus, there are not only deep cañons, but also vast depressions, descending to levels far below the sea, which are now filled with the earlier drift accumulations, or form channels submerged beneath ocean waves, or constitute basins occupied by lakes.
* The Fe2O3 was estimated by titration: the amount is certainly high; but the sp.g. of the powder (2.645) shows that it cannot be ascribed to the presence of epidote. 2·59% of Fe2O3 would be equivalent to an admixture of about 5·8% of epidote, which would demand a sp.g. of about 2·9 (cf. Cathrein, “Ueber Saussurit,” Zeits. f. Kryst. vii. 241–242).
page 208 note 1 loc. cit. pp. 208 and 219.
page 209 note 1 Geol. Wis. vol. i. p. 253.
page 209 note 2 Prof. Hilgard, E. W., Am. Journ. Sc., Nov. 1869, p. 333Google Scholar.
page 209 note 3 Val. Min. and Miss, to Junct. of Ohio; Gen. G. K. Warren, Rept. Eng., U.S.A., 1878.
page 210 note 1 Spencer, J. W., “Warping of the Earth's Crust,” etc., Am Nat., Feb. 1887Google Scholar.
page 210 note 2 J. W. Spencer, “The Miss. River, etc.” 1884. See also Coast Survey Charts.
page 210 note 3 Prof. Davidson, George, Bull. Cal. Acad. Sc., ii. 6, 1887, p. 265Google Scholar.
page 210 note 4 Lindenkohl, A., Appendix, No. 13, Rept. U.S. Coast Survey, 1884, pp. 270–273Google Scholar.
page 211 note 1 U.S. Coast Survey Charts.