JOHN WIvSLEY POWELL DAVIS 



Along with the other exploring geologists of that time, 

 Powell enjoyed the inspiring opportunity of working in a new 

 and extraordinary field, where the problems were impressive 

 in magnitude, yet relatively elementary in structure, and all 

 plainly disclosed under the denuding influence of a dry climate. 

 Facts which Nature elsewhere held as her secrets were there 

 openly proclaimed in imposing grandeur. Great series of de- 

 posits followed in orderly attitude and almost unbroken se- 

 quence ; deposition and denudation were measured in tens of 

 thousands of feet; unconformities were superbly exhibited. 

 Deformation had not gone so far as to produce almost unsol- 

 vable complications, but had sufficed to cause great faults and 

 flexures of simple pattern, and also to displace huge crustal 

 blocks, with only marginal disturbance, so that the structures 

 of this kind in the Plateau province, first clearly set forth by 

 Powell, became types for the world. The work demanded in 

 detecting the geological history of the region was utterly unlike 

 the detailed and technical investigation given year after year 

 by European observers to the overthrusts of the highlands and 

 the closed folds of the uplands of Scotland or to the overturns 

 of the Alps. Minute studies were not called for in the Plateau 

 country; conclusions were reached rapidly and large concepts 

 were strongly impressed on the observer. It was therefore but 

 natural that Powell's pathfinding geological work should be 

 treated in a style and on a scale prompted by the simplicity and 

 the magnitude of the great structural units with which he had 

 to deal. 



Powell used fossils only as guides to the dates of stratified 

 formations, not as a means of making out past forms of life. 

 His volcanic studies were free from complicated nomenclature, 

 guiltless of petrographical technique, and without bearing on 

 the classification of igneous rocks a subject that was then 

 taking modern shape. He briefly saw and named the Henry 

 Mountains during his canyon trip in 1869, and described them 

 as "composed of eruptive rocks in part" which had been 

 "poured out through some fissures here, and spread over the 

 country before it had been eroded to its present depth" (Colo- 

 rado River, 177) ; but his curiosity must have been aroused as 

 to what he did not see, for a few years later he had a special 



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