GOVEENMENT GEOLOGICAL SURVEYS 205 



vey commands our admiration for its brilliant plan, 

 thoroughgoing work in field and office, and high quality 

 of personnel. 



Major J. W. Powell began his large contribution to 

 Government surveys with his exploration of the Grand 

 Canyon in 1869, the Congressional recognition of his 

 expedition being limited to an authorization for the issue 

 of rations by the War Department. Small appropria- 

 tions were made in the following years, and in 1874 full 

 authorization was given for the continuance of his survey 

 in Utah under the Secretary of the Interior and was 

 followed by the adoption of the name " United States 

 Geographical and Geological Survey of the Rocky Moun- 

 tain Region." This organization was the least preten- 

 tious of the four operating during this period it covered 

 less area, expended less public money, and published much 

 less but its contribution to American geology is not to be 

 measured by miles or pages but by ideas. Its physical 

 environment favored this survey, and in the work of 

 Powell, Button, and Gilbert can be seen the beginnings of 

 physiography on the heroic scale exemplified in the 

 Grand Canyon and the High Plateaus. The first use of 

 terms like "base level of erosion," "consequent and 

 antecedent drainage," and "laccolith" marked the intro- 

 duction of new ideas in the interpretation of land sculp- 

 ture and geologic structure. The daring boat trip of 

 Powell was no less brilliant than his simple explanation 

 of the Grand Canyon itself. 



' ' The United States Geographical Surveys West of the 

 100th Meridian" was the title given to the explorations 

 made under Lieut. G. M. Wheeler, of the Engineer 

 Corps, which began with topographic reconnaissances in 

 Nevada, Utah, and Arizona, specifically authorized by 

 Congress in 1872. From the standpoint of American 

 geology this could be better known as the Gilbert Survey, 

 Mr. G. K. Gilbert serving for the three years 1871-73, the 

 later part of the time with the title of chief geological 

 assistant. Gilbert's contributions included his descrip- 

 tion of Basin Range structure, his first account of old 

 Lake Bonneville, and his discussion of the erosion phe- 

 nomena of the desert country. J. J. Stevenson nlso 

 served later as a geologist of this Survey, and A. R. Mar- 



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