] 
v. t 
, irrigation, or reclamation of swamp areas—are nm/le with 
Jient accuracy to be used iL the publication of maps on a 
of (1 inch = one-half mile), with a contour interval of 
purveys of areas in which there' are problem? of average 
importance, such as most of the basin of the Mississippi 
ts tributaries, are'made with sufficient accuracy to be used 
e publication of maps on a scale of ^55 (1 inch — nearly 
e), with a contour interval of 10 to 25 feet. 
Surveys of areas in which the problems are of minor 
c importance, such as much of the mountain or desert, 
of Arizona or New Mexico, are made with sufficient 
cy to be used in the publication of maps on a scale of 
inch = nearly 2 miles), with a contour interval of 25 to 
t. . 
pographic survey of Alaska has been in progress since 
and nearly 37 per cent of its area has now been mapped, 
t 10 per cent of the Territory has been covered by reeon- 
nee maps on a scale of » or about 10 miles to an 
Most of the remaining area surveyed in Alaska has 
O - a.' 
mapped on a scale of hut about 4,000 square mules 
een mapped ou a scale of 
out half of the Hawaiian Islands has been surveyed, and 
lilting maps are published on a scale of 5 ^ 55 . 
e features shown on these maps may be arranged in three 
) 8 —( 1 ) water, including seas, lakes, rivers, canals, swamps, 
Dtlier bodies of water; ( 2 ) relief, including mountains, 
valleys, and Other features of the land surface; (3) culture 
:s of man), such as towns, cities, roads, railroads, and 
