MAPS OF THE UNITED STATES 
Iconventional signs used to represent these 
| and explained below. Variations appear on 
and additional features are represented on 
tures are represented in blue, the smaller 
by single blue lines and the larger streams, 
ea by blue water lining or blue tint. Inter- 
ose whose beds are dry for a large part of 
n by lines of blue dots and dashes, 
by contour lines in brown, which on some 
nted by shading showing the effect of light 
orthwest across the area Tepreseuted, for the 
the appearance of relief and thus aiding iu 
f the contour lines. A contour line repre¬ 
line on the ground (a contour) every part 
same altitude above sea level. Such a hue 
any altitude, but in practice only the con¬ 
sular intervals of altitude are shown. The 
itself is a contour, the datum or zero of alti- 
a level. The 20-foot contour would be the 
a should rise 20 feet. Contour lines show 7 
11s, mountains, and valleys, as well as their 
ve contour lines that are far apart on the 
tie slope; lines that are close together in d i- 
ami lines that run together indicate a cliff, 
which contour lines express altitude, form, 
in the figure below. 
n>s 
psents a river valley that lies between two 
ground is tbe sea, with a, bay that is partly 
id sand bar. On each side of the valley is 
h small streams have cut narrow gullies, 
lit has a rounded summit and gently slop- 
hy ravines. The spurs are truncated at 
their lower ends by a sea cliff. The hill at the left term] 
abruptly at the valley in a steep scarp, from which it j 
gradually away and forms an inclined table-land that i 
ersed by a few shallow gullies. On the map each of 
features is represented, directly beneath its position i 
sketch, by contour lines. 
The contour interval, or the vertical distance in feet b 
one contour and the next, is stated at the bottom of eac* 
This interval differs according to the topography of th 
mapped: in a flat country it may be as small as 1 foot 
mountainous region it may be as great as 250 feet, 
contour lines, every fourth or fifth one, are made heavier 
the others and are accompanied by figures showing al 
The heights of many points—such as road comers, a 
surfaces of lakes, aud bench marks—are also given on th 
in figures, which show altitudes to the nearest foot only, 
exact altitudes— those of bench marks—as well as the gel 
coordinates of triangulation stations, are published in bu 
issued by the Geological Survey. 
Lettering and the works of man are shown in black, 
aides, such as those of a State, county, city, land grant, 
ship, or reservation, are shown by continuous or broken 
of different kinds and weights. Metaled roads are show) 
double lines, one of which is accentuated. Other public 
arte shown by fine double lines, private and poor roa< 
dashed doable lines, trails by dashed single lines. 
Each quadrangle is designated by the name of a city, 
or prominent natural feature within it, and on the mar 
the map are printed the names of adjoining quadran 
which maps have been published. Over 8,000 quadrang| 
the United States have been surveyed, and maps of 
similar to tbe one on the other side of this sheet have 
published. • 
The topog^phic map is the base on which the geo! * 
mineral resources of a quadrangle are represented, an« 
maps showing*these features are bound together with a de 
tive text to form a folio of the Geologic Atlas of the U 
States. More than 200 folios have been published. 
Index maps of each State and of Alaska and Hawaii sh< 
the areas ^-verted by topographic maps and geologic folios 
lished by rare United States Geological Survey may be ob 
free. Copies of the standard topographic maps may be ohi 
for 10 cent- o**h; some special maps are sold at different 
A discount of 40 per c-nQ allowed o n an order fqO 
amounting to $5 or more at the retail price. Th* 
folios are sold, for 2o cents or more each, the price dtpeij 
on tbe size of the folio. A circular describing the foil 
be sent on request. 
Applications for maps or folios should be accompani 
cash, draft, or money order (not postage stamps) aid shon 
addressed to 
THE DIRECTOR, 
United Stales Geological Survey 
Washington, 
January, 1924. 
VENTIONAL SHTNS 
CULTURE 
(printed in black ) 
I |_ 
loa.de Electric 
Lotions raih'Oiul 
Tunnel 
Wbax'ves 
Breakwater 
andjetties 
Bridges 
Drawbridges Ferry 
f pofn* up*tr*mm ! 
Ford 
1-4-4 
, i 
1 i 
—___i_J 
ril Township Reservation Laud grant (dtr village, or Small park or TriauriilaJidj F.S.tumeral 
r tine ,u " ■* -e— - 
I' district lim 
I 
Mrue or 
quarry 
Z 
Sueams 
line 
borough hue cemetery line or primary monument 
1 raverse manumeut 
Bonulftiy 
monument. 
r * —i 
1 ! 
—_1 
- I 
A 
L 
Prospect 
“I 
si L M 
Shall 
L_ 
Mine tunnel Mine tunnel Lighthouse Light- ship 
• sfic/U't Hy dit velum ) OP U0ftCOU 
Life-saving 
st'itiao 
WATER 
(printed in blue) 
Jsa 
Falls and 
rapids 
; nterxni ttent 
streams and 
ditches 
£ 
Canals or Aqueducts ur Aqueduct Late or Unsixr'vcyed 
ditches -waterpmes tunnels pond stream and 
abaxsdemod cam al 
LJ 
Intermittent Glacier Mpiing Well Salt marsh fresh marsh Grassy pnud 
lake ** 
prbtl+rf tr*; bln*} % 
Tidal Hots 
WOODS 
vhen shown, printed in green) 
