DESCRIP’ 
0GRAP1 
The United States Geological Si 
a topographic map of the Unitec cp> 
work has been in progress since 
three-tenths of the area of the con 
outlying possessions, has been map 
peel areas are widely scattered, ne<‘ 
being represented as shown on tb 
accompanying eaih annual report 
This great map is being publish 
of convenient size, which are bom 
and meridians. The four-coni' 
land corresponding to an atlas i 
quadrangle . The sheets are of a 
same size: the paper dimensions 
inches; the mep- occupies abou 
height and Hi to 16 inches of 
varying with latitude. Three sc 
employed. The largest scale is 
nearly one mile to one inch; i. e 
on the ground is represented by < 
ox*/ 
the map. This scale is used for 
or industrially important parts 
For the greater part of the count 
scale of 1:125000, or about two 
is employed. A third and stil 
1:250000, or about four miles to one inch, has 
been used in the desert regions of the far West. 
A few special maps on larger scales are made of 
limited areas in mining districts. The sheets on 
the largest scale cover 15' of latitude by 15' of 
longitude; those on the intermediate scale, 30' of 
latitude by 30' of longitude; and those on the 
smallest scale, 1° of latitude by 1° of longitude. 
The features shown on this map may, for con- 
venience, be classed in three groups; (1) water , 
including seas, lakes, ponds, rivers and other 
breams. oanaF ci-nmns. etc.; (2) relief ‘ including 
;de. 
own, not by i 
lies. Ponds 
, year are sh< 
water marshes 
I 
S persed with 
ties and swai 
zontal lines. 
1 r* i shown by < 
ur passes thn 
One win 
will go neith 
evel. By the 
ipes of the pla 
t also the elevi 
;elf is a contoui 
n being mean j 
• jr, 20 feet above 
the seacoast if tJ 
- ik 20 feet. Si 
r s and forward t 
. On a gentle g 
i 
the present com 
» near it. Thus | 
; far apart on til 
close together, a 
contours run together in ( 
vertically under the one ? 
cliff. In many parts of tl 
or hollows with no outlets, 
surround these, just as tin 
small hollows known as si 
by hachures, or short das) 
curve. The contour inte 
tance in feet between one 
stated at the bottom of ei 
varies according to tin 
manned : in a flat countn 
