[39] Acids and bases combined according to the principles indicated by Bunsen.
[40] Chemical Geology, Vol. I, pp. 76, 77, English ed., 1854.
[41] Allgemeine und chemische Geologie, Vol. I, pp. 456, 457. 1879.
[42] Russell. Rivers of North America, p. 79.
[43] For disastrous floods of the lower Mississippi, see Johnson, Bull. Geol. Soc. Am., Vol. II, pp. 20–25. For effect of precipitation and forests on floods, see Russell’s Meteorology, pp. 198–217, and Vermeule, Report on Water Supply, Geol. Surv. of N. J.
[44] An excellent discussion of this subject is given by Gilbert in The Henry Mountains, pp. 99 et seq., and more briefly in the Am. Jour. Sci., Vol. XII, p. 85 et seq. 1876.
[45] Jour. of Geol., Vol. IV, p. 718. An excellent summary of the principles of Rock Weathering.
[46] Russell. Rivers of North America, p. 17.
[47] W. G. Thompson. Nature, Vol. I, p. 555, 1870. The Matapediac River, N. B. Cited by Russell in Rivers of North America, p. 25.
[48] Dutton. Tertiary History of the Grand Canyon District, Mono. II, U. S. Geological Survey.