NATIONAL ACADEMY BIOGRAPHICAL MEMOIRS VOL. VIII 



beds had not been carried away they would now be found more 

 than % twenty- four thousand feet above the river" (Colorado 

 River, 152, 153). This is an admirable statement of a great 

 idea. It bears not only upon the processes of river evolution, 

 but upon the fundamental principles of geology. It was a wel- 

 come reinforcement of the arguments for unjf nrrnitui iuiiiLTn, 

 which, though valiantly urged by Hntton^ Playf ajr, and Lyell 

 regarding processes of erosion and deposition, were even later 

 than the middle of the nineteenth century not entirely success- 

 ful in. vanquishing the widespread traditional belief in violent 

 processes of deformation and upheaval. Powell's demonstra- 

 tion, as he thought it, that the Uinta Mountains were not lifted 

 up faster than the Green River could cut its canyon down 

 through their broad anticline had great influence in convincing 

 his contemporaries that uplift as well as erosion and deposi- 

 tion is a slow process, and thus aided, the gentle doctrine of 

 geological peace on earth gained a vast backward extension 

 into periods of the past that had long been conceived as ages 

 of violence. 



It was to rivers which, like the Green in the Uintas, had 

 held their course through an area of adverse uplift that Powell 

 gave the excellent name of antecedent. He appears to have 

 made no search whatever to learn whether other observers had 

 come upon the same idea ; not that he was in the least disposed 

 to claim priority by neglecting their labors, but that he was 

 fully engrossed in his own. In a thorough review of this prob- 

 lem, Penck* points out that Medlicott in India and Hayden in 

 the United States had both preceded Powell in recognizing the 

 persistence of certain rivers in holding their courses through 

 slowly uplifted mountain ranges. Medlicottf inferred the long 

 persistence of certain rivers and the slow, imperceptible prog- 

 ress of deformation and uplift, because of "marked corre- 

 spondence between the distribution of the accumulations of 

 conglomerate [ancient piedmont river deposits] and the posi- 

 tion of actual river gorges" through the outer ranges of the 



* A. Penck. Die Bildung der Durchbruchstaler. Verein z. Verbr. 

 naturwiss. Kenntnisse in Wien, 1888. 



t H. B. Medlicott. The Alps and the Himalayas. A geological com- 

 parison. Quart. Journ. Geol. Soc., XXIV, 1868, pp. 34-52. 



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