BY-PKODUCTS OP MINEEAL-LAND CLASSIFICATION. 157 



water, though not generally understood by the layman, are yet com- 

 paratively simple, and a glance at the geologic map of a region may 

 indicate at once the most favorable locality for sinking a well. As 

 a minor illustration of the value of such information may be men- 

 tioned the fact that one of the geologists of the Survey had occasion 

 during the summer of 1912 to advise two newly arrived settlers in 

 the ceded lands of the Crow Indian Reservation, Mont., to sink 

 their wells on the east side of a ridge rather than on the west side, 

 as they had intended, because of the simple geologic fact that the 

 rocks dip slightly to the east and the water follows down the dip, 

 as is proved by the numerous springs on the east side and the few 

 on the west. Such information is, of course, only of local applica- 

 tion, but as the western country becomes more thickly settled and 

 questions relating to city water supply arise, information of this 

 kind gathered for the primary purpose of land classification may 

 prove to be of considerable value. 



Miscellaneous data of these types are utilized in various ways. 

 Such of them as can with propriety be so used may be published in 

 the bulletins in, which the geologic material assembled in the course 

 of land classification is made available for public use. Others, al- 

 though not published and not used in mineral-land classification, 

 are of the greatest value to the department in administering laws 

 relating to nonmineral land, like the enlarged-homestead act, the 

 desert-land law, or the Carey acts. Still others represent merely the 

 accumulation of data likely to be needed if certain moot questions 

 concerning public lands are to be decided by future legislation. All 

 these actual or prospective uses, however, either directly or indirectly 

 concern the public at large. 



DATA RELATING TO PROSPECTING AND jNIINING. 



Information regarding the character, location, and extent of each 

 stratum of economic importance in the area examined forms a large 

 part of the data on which classification is based. This information 

 is published by the Survey in special bulletins or in the annual 

 " Contributions to economic geology." A study of the map and 

 of the plates of sections taken on the coal beds in any field, for ex- 

 ample, will indicate to the prospective operator the most favorable 

 location for a mine, and the text includes observations concerning 

 the cover of the bed, the character of the roof and floor rocks, and 

 the general structure, including faulting, of the inclosing strata. 



Aside from the local and particular facts recorded for each area, 

 as this work progresses the extent and character of each of the great 

 mineral-bearing provinces are being accurately determined and more 

 and more comprehensive and definite data concerning the mineral 

 wealth available for the Nation's use are being gathered. 



