NATIONAL ACADEMY OF SCIENCES. 



portant stages in the geological history of the Cordilleran system. 

 It was probably the most masterly summary of a great piece of 

 geological work that has ever been written, and was well charac- 

 terized by its most competent critic in the following words : 



"The most satisfactory part of Mr. King's work, next to its 

 scientific thoroughness, is the breadth of view which embraces 

 in one field the correlation of such extended forces and the vigor 

 of grasp with which the author handles so large a subject with- 

 out allowing himself to be crushed by details. Hitherto every 

 geological report has been a geological itinerary without general- 

 ization or arrangement. This volume is much more ; it is indeed 

 almost a systematic geology in itself, and might be printed ir^ 

 cheaper form and used as a text-book in the technological 

 schools." 



Aside from the direct contributions to science embodied in the 

 seven quarto volumes that contained the published results of this 

 great survey, King exerted a most important influence upon 

 geological work in this country by the high standards he set for 

 it and his practical demonstration of the possibility of living up 

 to them. Thus a topographic survey which should afford an 

 accurate delineation of the relief of a country had not hitherto 

 been considered a necessary base for geological mapping either 

 in State #or government surveys. A system of rapid surveying 

 by triangulation and the use of contours to express relief was 

 first employed by him. in making maps of large areas, and inaug- 

 urated an improvement in our systems of cartography that has 

 made the maps issued by our government superior to any in the 

 world. He demonstrated the importance of the general use of 

 photography as an adjunct to geology, which previously had not 

 been considered practicable because of the labor and expense 

 involved in transporting the necessary apparatus for the develop- 

 ing of wet plates in the field. Of even greater moment was the 

 practical introduction of the methods of microscopical petrog- 

 raphy, supplemented by chemical analysis, in the examination of 

 rocks — an innovation which marked the opening of a new era 

 in geological study in the United States. 



His mind was possessed in a high degree of the quality, known 

 as scientific imagination, that enabled it to grasp almost at a 

 glance the ultimate bearing of observed phenomena on the 



42 



