24 THE UNITED STATES GEOLOGICAL SURVEY. [bull. 227. 
the library, through publications of the Survey, purchases, donations, 
and exchanges, the working force has been increased until it now 
consists of 9 persons, including the librarian in charge. 
Under the law the library is open from 9 a. m. until 4.30 p. m. 
During these hours it is in constant use by outside students as well as 
by members of the Survey. The latter are permitted, in addition, to 
draw from the library any books, except encyclopedias and diction- 
aries, that are needed by them in their investigations. 
The work of the Geological Survey has a wide range in the domain 
of science and economics. It is recognized that the library should 
completely cover the held of geology in its broadest sense, including 
the practical, historical, and bibliographic ground. The endeavor is 
made to procure all publications needed for reference in geology, 
geography, engineering, statistics, chemistry, and plrysics, and for 
administrative purposes. This standard of completeness has not been 
reached, but it is believed that the library of the Geological Survey 
approaches it more nearly than any other, except, perhaps, that of the 
Geological Society of London. 
GEOLOGIC BRANCH. 
The geologic branch is composed of four divisions: (1) Geology and 
paleontology; (2) Alaskan mineral resources; (3) mining and mineral 
resources; (4) chemical and physical researches. 
DIVISION OF GEOLOGY AND PALEONTOLOGY. 
Previous to the organization of the United States Geological Survey, 
in 1879, there had existed various organizations in which men had 
been trained and investigations started. The newly organized Survey 
inherited much unfinished work from these different surveys pre- 
viousl} T prosecuted under the auspices of the Government in the 
Western Territories. Since it seemed desirable to carry forward and 
complete these surve} r s as rapidly as possible, investigations were con- 
tinued in the fields covered by them, and thus the early organization 
of the Survey was determined in part by antecedent geologic work. 
At the same time, however, demands for local economic investigations 
came from various portions of the country, and new investigations 
were consequently begun. 
The history of the division of geology and paleontology may be 
divided into four periods: (1) From the organization of the Survey in 
1879 to 1884, during which there was a process of differentiation of 
the various lines of work that were being carried on; (2) from 1884 
to 1893, during which geologic work was organized under divisions 
based in part on the subject-matter under investigation, but largely 
on geographic provinces; (3) from 1893 to 1899, during which work 
