98 THE POPULAR SCIENCE MONTHLY. 



Resources of the United States appears annually and makes 

 known not only the figures of production but also the numerous 

 theoretical considerations which interest the miner. 



As to the geographic work which the Geological Survey also 

 possesses among its attributes, a numerous personnel of topogra- 

 phers and engineers work actively at the execution of the map in 

 the most diverse parts of the country under the direction of Mr. 

 H. Gannett. Already more than six hundred sheets have been 

 surveyed and drawn, and about four hundred have appeared. 



Besides geology and geography ought to be mentioned a con- 

 siderable work, of which Mr. Powell is the founder, in the domain 

 of the pre-Columbian archaeology, the linguistics, the ethnology, 

 and the anthropology of the Indians of North America, splendidly 

 illustrated by Mr. Holmes. The last publication of Mr. Powell 

 upon the classification of American languages is, according to the 

 best judges, of great importance. 



Not being able to give here a complete list of all the actual 

 collaborators of the survey, or of their services, we must content 

 ourselves with noticing those who have taken the principal part 

 in the execution of the works already published. These are in 

 alphabetical order : Messrs. Becker, Chamberlin, Cross, Davis, 

 Day, Diller, S. F. Emmons, Fontaine, Gannett, Gilbert, Hague, 

 Hayes, Holmes, Iddings, McGee, Marsh, Newberry, Peale, Russell, 

 Shaler, Van Hise, Walcott, Ward, Upham, Weed, C. A. White, 

 Whitfield, A. Williams, G. H. Williams, and H. S. Williams. It 

 is but just that we should not omit the names of those who are 

 dead : Messrs. Hay den, Irving, Lesquereux, Leidy, Marvine, and 

 Newton ; or of those who no longer belong to the survey : Messrs. 

 Bradley, Cope, Curtis, Dutton, Endlich, Hill, Howell, Clarence 

 King, St. John, Stevenson, and Wheeler. Many of these names 

 will remain justly illustrious. 



It will be impossible to give in this report even a summary 

 idea of the most remarkable discoveries which are due to the 

 Geological Survey. They belong to branches very diverse: re- 

 gional geology, monographs concerning metalliferous deposits, 

 general and comparative stratigraphy, mineralogy and petrogra- 

 phy, volcanic phenomena, glacial phenomena, ancient Quaternary 

 lakes, and a history of the Atlantic littoral. 



Among the most considerable results must be mentioned the 

 paleontological discoveries made in the Rocky Mountains. Since 

 the day in which Hayden undertook his memorable explorations, 

 we have learned that the site of the Rocky Mountains was con- 

 tinuously a part of the continent during the greater portion of 

 the Secondary, Tertiary, and Quaternary epochs. Upon this vast 

 continent the quadrupeds could develop during extended time, 

 freely, without any interruption to their evolution, and thus they 



