GENERAL RESULTS ACHIEVED. 15 
graphed on stone the colors, ranging in number from 10 to nearly 30, 
necessary for distinguishing in each of about 100 geologic folios the 
various formations and outcrops. It has printed several editions of 
most of the topographic maps and at least one edition of the geologic 
folios, besides revising both as occasion therefor has arisen, and 
engraving and printing miscellaneous State and United States maps. 
The hydrographic branch (see pp. 71-93), including the reclamation 
service, has recorded during the last fifteen years the maximum, mini- 
mum, and mean discharges of all the more important rivers, and for 
shorter periods the same facts concerning all the lesser tributaries of 
the many hundreds of streams in the United States. These results 
have been assembled 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 characteristics of the river basins have been 
studied in respect to their forestation, soil covering, etc., and there 
has been accumulated a vast amount of data from which it is possible 
to estimate closely the volume or run-off of each of the streams. The 
development of the water powers of the country, especially 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 discbarge 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 
resulting 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examined and surveyed in a preliminary way, and the lands withdrawn 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, survej^s of the irrigable lands, as well as of canal lines, have 
been made, and some have been finally approved for construction by 
the reclamation service. (See pp. 91-93.) 
The division of geography and forestry (see pp. 71-71) has made 
detailed examinations of 110,000 square miles, including a classi- 
fication of the lands, as forested (with stand and kind of timber), grazing, 
desert, and cultivable, and has prepared 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 Geo- 
logical Survey is best shown by the aid it extends in developing 
the mineral resources and in forwarding important engineering 
projects in which the people, as well as the State and Federal Gov- 
ernments, are interested.* To instance a few cases: The work of 
