Chapter IV

Babb. _Science_, Vol. XXI, p. 343. 1893.
Clarke. _Data of Geo. Chemistry. Geol. Sur., U.S.A. Bull. 491._
—— _Smith. Misc. Collect._, Vol. LVI, No. 5. 1910.
Dittmar. _Challenger_ Report, Vol. I, p. 203. 1884.
Dole and Stabler. _Water Supply Papers. Geol. Sur., U.S.A._,
Nos. 234 and 236. 1910.
Geikie. _Trans. Geol. Soc., Glasgow_, p. 153. 1868.

Humphreys and Abbott. _Physics and Hydraulics of Mississippi River_,
p. 148. 1876.
Merrill. _Rocks, Rock weathering and Soils._ 1897.
Murray. _Scot. Geog. Mag._, Vol. III, p. 65. 1887.
—— _Scot. Geog. Mag._, Vol. IV, p. 38. 1888.
Reade. _Chemical Denudation in Relation to Geological Time._ 1901.
Russell. _River Development._ 1898.
Schwarz. _Causal Geology._ 1910.
Tylor. _Phil. Mag._, April, p. 258. 1853.