National Geographic : 1890 May
110 National Geographic Magazine. Hayden was perhaps the first to point out in this country the antecedent origin of certain headwaters of the Missouri in Mon tana, where the mountain ranges are frequently cut across by deep cautions. Amer. Journ. Science, xxxiii, 1862, 305. Hayden's Sixth Report, 1872 (1873), 85. Reference may be made also to White, Hayden's Tenth Report, 1876 (1878), 52 ; Peale, id., 167 ; Bechler, id., 372. General dis cussion of valley making is given by Green, Geology for students and general readers, London, 1876 ; Hartung, Zeitschr. Gesellsch. f. Erdkunde, Berlin, 1878, 308. In spite of the early date of some of these essays, the idea of the antecedent origin of rivers did not gain general recognition and acceptance till it was strongly stated by Powell.