68 THE U. S. GEOLOGICAL SURVEY 



lands suitable for enlarged and stock-raising' homesteads, of 

 water-power and reservoir sites, and of public water reserves. 

 A systematic classification of oil-shale lands has been under- 

 taken and is still in progress, such lands being, however, classi- 

 fied only as mineral. No systematic classification has been 

 attempted of mineral lands generally 1X or of desert lands. 



The first step in the systematic examination and classifica- 

 tion of an area thought likely to contain mineral or water 

 resources, bringing it under special provisions of law, involves 

 several distinct stages — that of withdrawal of the lands from 

 entry pending classification, that of examination and classifica- 

 tion, and, in the case of coal lands, evaluation, and that of 

 restoration of the lands to entry. 



Withdrawals for purposes of classification are recommended 

 by the Survey as soon as it finds probable cause for believing 

 that a given area contains lands falling under any of the spe- 

 cial designations above referred to as calling for systematic 

 classification. The facts upon which such belief is based may 

 result from the Survey's own explorations or may be com- 

 municated by private parties, or may come to the attention of 

 the Survey through news of the discovery of mineral deposits 

 in areas not hitherto thought to contain such deposits. 



The recommendations of the Survey as to withdrawals are 

 made direct to the Secretary of the Interior, who, in turn, 

 refers them to the President with his recommendations. 



The extent of field examination found necessary for the 

 classification of an area depends of course upon the amount 

 of data already available to the Survey as a result of investi- 

 gations previously made by it in the area, whether for classi- 

 fication or for other purposes, or those which may have been 

 made by the field force of the General Land Office. Generally 

 speaking, a previous systematic geological survey of an area 



11 By act of June 25, 1910 (36 Stat. L., 739) special provision is 

 made for the classification of the lands within the Northern Pacific 

 Railroad grant with respect to their mineral or non-mineral charac- 

 ter. Work under this provision has been in progress since 1910. 



