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The National Geographic Magazine 



shorter periods the same facts concern- 

 ing all the lesser tributaries of the many 

 hundreds of streams in the United 

 States. These results have been assem- 

 bled and studied, and the flow of the 

 streams has been compared with the 

 precipitation as shown by the records of 

 the Weather Bureau. The physical 

 t characteristics of the river basins have 

 been studied in respect to their foresta- 

 tion, soil covering, etc., and there has 

 been accumulated a vast amount of 

 data from which it is possible to esti- 

 mate closely the volume or run- off of 

 each of the streams. The development 

 of the water powers of the country, 

 especialty in the Southern States, has 

 received a great impetus in the last few 

 years through the facts brought to light 

 by the hydrographic branch in respect 

 to the volume and regularity of the dis- 

 charge of and the amount of fall in the 

 various streams of the country. Many 

 unknown water powers have been found , 

 and projects already commenced have 

 had their value or their defects made 

 manifest through the evidence result- 

 ing from the surveys of this branch. 

 Data have been gathered concerning the 

 public lands which are irrigable and 

 their relation to possible water supplies. 

 A large number of reservoir sites have 

 been examined and surveyed in a pre- 

 liminary way, and the lands withdrawn 

 from sale or occupation pending more 

 detailed studies. A number of these 

 reservoir and irrigation projects have 

 been studied in greater detail, surveys 

 of the irrigable lands, as well as of 

 canal lines, have been made, and some 

 have been finally approved for construc- 

 tion by the reclamation service. 



The division of geography and for- 

 estry has made detailed examinations 

 of 110,000 square miles, including a 

 classification of the lands, as forested 

 f with stand and kind of timber) , graz- 

 ing, desert, and cultivable, and has pre- 

 pared 'final reports on these reserves, 

 showing the character and amount of 

 the timber and many other facts which 



will serve as a basis for the future forest 

 management of these properties. 



Perhaps the immediate value to the 

 people of the work of the Geological 

 Survey is best shown by the aid it ex- 

 tends in developing the mineral re- 

 sources and in forwarding important 

 engineering projects in which the peo- 

 ple, as well as the state and federal 

 governments, are interested. To in- 

 stance a few cases : The work of the 

 geologic branch has had a wide edu- 

 cational influence upon the public at 

 large, but more directly upon those en- 

 gaged in the mining industry. Among 

 the many direct practical benefits which 

 it has conferred upon this industry may 

 be mentioned the investigation of the 

 mining geology of Leadville, which has 

 not only guided exploration and secured 

 economical mining in a district that has 

 produced between $200,000,000 and 

 $300,000,000, but has been of even more 

 beneficial result in teaching the mining 

 engineer and the miner the practical 

 importance of geologic study in carry- 

 ing on the work. In other words, it 

 has greatly improved mining methods 

 throughout the whole country. The 

 investigation of the origin and geologic 

 relations of the Lake Superior iron ores 

 and the publication of numerous re- 

 ports on that region have so effectively 

 directed the prospector in the discovery 

 of the deposits and the miner in eco- 

 nomical methods of development that 

 this region now leads the world in the 

 production of iron ore. The detailed 

 areal mapping and the determination of 

 underground structure in the Appa- 

 lachian coal fields are placing the de- 

 velopment of its coal, petroleum, and 

 gas resources upon a scientific basis and 

 relieving these branches of the mineral 

 industry of a large part of the hazard 

 and uncertainty which has always hith- 

 erto been associated with them. The 

 collection and publication of reliable 

 statistics of mineral production have 

 furnished a sound commercial basis for 

 all branches of the mineral industry. 



