16 THE UNITED STATES GEOLOGICAL BUEVEY. [bull.227. 
the geologic branch has had a wide educational influence upon the 
public at large, but more directly upon those engaged in the mining 
industry. Among the many direct practical benefits which it has con- 
ferred 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 8800,000,000, but has been of even more beneficial 
result in teaching the mining engineer and the miner the practical 
importance of geologic stud}^ in carrying on their 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 reports on 
that region have so effectively directed the prospector in the discovery 
of the deposits and the miner in economical 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 Appalachian coal field are placing the development of 
its coal, petroleum, and gas resources upon a scientific basis and reliev- 
ing these branches of the mineral industry of a large part of the hazard 
and uncertainty which has always hitherto been associated with them. 
The collection and publication of reliable statistics of mineral produc- 
tion (see pp. 48-5<») have furnished a sound commercial basis for all 
branches of the mineral industry. 
ADMINISTRATIVE BRANCH. 
EXECUTIVE DIVISION. 
This division is in general charge of the chief clerk. It embraces 
three sections: (1) Correspondence, records, supplies, and shipments; 
(2) instruments; and (3) messenger, watch, and labor force. 
Section of Correspondence, Records, Supplies, and Shipments. 
This section is the successor of a miscellaneous division which was 
established early in 1SS5. That division had charge of the preparation 
of letters and reports, without restriction as to subject, a class of work 
which was then and for years afterwards done under the immediate 
control of the Director and the chief clerk, and not by the heads of 
branches, divisions, and sections, as at present. The old division also 
attended to the incoming mail, opening, recording, and referring or 
otherwise acting upon it, and to matters relating to appointments and 
attendance, much as is done under the present organization; but it did 
not have charge of property accounting, supplies, or shipments. In 
May, 1901, the division was reorganized on broader lines, its functions 
were enlarged, and its force of two or three persons was much increased; 
the force employed in the section now numbers 12. Recently the more 
specific name given above was adopted. 
