HIC MAP OF THE UNITED STATES 
(full lines, but by lines of 
i 7 U 
which are dry darina: a 
lovvu by oblique parallel 
s are shown by horizontal 
tufts of blue, and fresh- 
imps by blue tufts with 
contour lines in brown. 
ough points which have 
who follows h contour on 
S' n’"'l 1 
contours not only 
J 
A ins, hills, and mountains 
'atious. The line of the 
,r line, the datum or zero 
sea level. The contour 
i sea level is the line that 
the sea were to rise or the 
ucli a line runs back up 
j around the points of hills 
slope this contour line is 
ast line, while on a steep 
i a succession of these con- 
the map indicates a gentle 
a steep slope; and if the 
| one line, as if each were 
1 above it, they indicate a 
the conn try are depressions 
s. The contours of course 
hey surround hills. Those 
sinks are usually indicated 
shea, on the inside of the 
cerval, or the vertical dis- 
b contour and the next, is 
each map. This interval 
uc character of the area 
their descriptions, as well as the descriptions and 
geodetic coordinates of triangulation stations, are 
published in the annual reports and bulletins of 
the Survey. The publications pertaining to speci¬ 
fied localities may be had on application. 
The works of man are shown in black, in which 
color all lettering also is printed. Boundaries, 
such as State, county, city, land-grant, reservation, 
etc., are shown by broken lines of different kinds 
and weights. Cities are indicated by black blocks, 
repres e nti ng th e- huilt-nn p ortions, and country 
houses by small black squares. Roads are shown 
by fine double lines (full for the better roads, dot¬ 
ted for the inferior ones), trails by single dotted 
lines, and railroads by full black lines with cross 
lines. Other cultural features are represented by 
conventions which are easily understood. 
The sheets composing the topographic atlas are 
designated by the name of a principal town or of 
some prominent natural feature within the district, 
and the names of adjoining published sheets are 
printed on the margins. The sheets are sold at 
five cents each when fewer than 100 copies are pur¬ 
chased, hut when they are ordered in lots of 100 
or more copies, whether of the same sheet or of 
different sheets, the price is three cents each. 
The topographic map is the base on which the 
facts of geology and the mineral resources of a 
quadrangle are represented. The topographic and 
geologic maps of a quadrangle are finally bound 
together, accompanied by a description of the dis¬ 
trict, to form a folio of the Geologic Atlas of the 
United States. The folios are sold at twenty-five 
cents each, except such as are unusually compre¬ 
hensive, which are priced accordingly. 
Applications for the separate topographic. 
r r. far fnliog 
