THE UNITED STATES GEOLOGICAL SURVEY. 481 



cial attention was given to tlie consideration and solution of cer- 

 tain broad geologic problems presented by the wide domain of 

 the United States. These problems embraced those of the geo- 

 logic growth and development of a great continent, many of 

 which had to be solved before the areal geographic mapping 

 could be carried forward intelligently and with due consideration 

 for scientific accuracy and economy. With the completion of 

 topographic sheets, areal geology was gradually taken up, and in 

 1894 more than three fourths of the available geologic force was 

 employed in areal work. 



The scope of the work of the Geological Survey has thus come 

 to include the preparation of a topographic base map of the entire 

 United States ; the study and mapping of the areal geology upon 

 this base ; the examination of the geologic structure and mineral 

 resources of the national domain ; the gathering of the statistics 

 of mineral production ; the study of the artesian and surface 

 water supply of the United States ; and, indirectly, the mineral 

 and agricultural classification of the public lands under survey. 



There is one fact that should be borne in mind when consider- 

 ing the scope of the work, and that is that the Geological Survey 

 is a bureau of research. Its work is to a large extent the discov- 

 ery of unknown facts and principles, and the scientific co-ordina- 

 tion of these and all known facts and inductions, within the scope 

 of its work, in such a form that they shall subserve the use of 

 both the Government and the people; the latter to include not 

 only the farmer, prospector, miner, owner of lands, investor, and 

 mining and civil engineer, but also the most highly trained stu- 

 dents, teachers, and specialists. 



Topographic Base Map. Captain George M. Wheeler said 

 of topographic surveys : " The topographic is the indispensable, 

 all-important survey, being general and not special in its charac- 

 ter, which underlies every other, including also the graphic basis 

 of the economic and scientific examinations of the country. . . . 

 This has been the main or principal general survey in all civilized 

 countries, and all other so-called surveys (as geodetic, trigonomet- 

 ric, etc.) are but accessories or addenda thereto. . . . The results 

 of such a survey become the mother source whence all other 

 physical examinations may draw their graphic sustenance."* 



A recent European writer f (1892) on the general topographic 

 maps of the present time says that all European states have un- 

 dertaken uniform and continuous topographic surveys of their 



* Facts regarding the Origin, Organization, etc., of Government Land and Marine Sur- 

 veys of the United States. 1885. 4to pamphlet. Washington, D. C. : War Department. 



f C. Lowinsin Ymer. Tidskrift utgiven af Svenska Sallskapet for Antropologi och Geo- 

 grafi. 1891. Elfte argangen, 3e och 4e haft (slut). Stockholm: Samson & Wallin, 1892. 

 VOL. XL VI. 35 



