GEOLOGY IN THE UNITED STATES 55 



interior. The survey was organized in four branches, geolog- 

 ical, topographical, publication, and administrative, and 

 within each of these are several divisions. Since its establish- 

 ment, nearl}^ fifty thousand square miles have been survej^ed 

 topographically, the survey being of special service during the 

 past two years in the development of mineral resources, as 

 well as contributing a vast amount of knowledge to the science 

 in general. 



