orks of man), m**h as (own8, nils*, ’\Ws, railroads ; !Li( J 1L) o oj-.-ira ,-jv . - ^ L y -ravin**. ' h. , ;, w: • re mii-iiL- 
uudariee. The symbols used to represent these features are their lower end* by a sea cliff. 'I'he hill at the left term in 
own and explained below. Ya.nat.ions appear on some eadjer abrupt.i v it the v ; ,ilry m a siee-i s-an;., T'mj which it f l< 
ape, and additional features are represented on some special gradually away and forms an inclined tabled and that i> t] 
ips. ersed by a few .-hr lh.>v,-’ gullies. On 1b e map each of t| 
All the water features are represented in blue, the smaller features is represented, directly beneath its position in 
and canals by single blue lines and the larger streams, sketch, by contour lines, 
e lakes, and the sea by blue water lining or blue tint. Infer- The contour interval, or th I 
ittent streams—those whose beds are dry for a large part of one contour and the next, is stated at the bottom of each U| 
e year—are shown by lines of blue dots and dashes. This interval differs according to the topography of the 
Relief is shown by contour lines in brown, which on some mapped: in a flat country it may be as small ag 1 foot; 
sips are supplemented by shading showing the effect of light mountainous region it may be as great as 250 feet Cet 
urpove of giving the appearance of relief and thus aiding in the. others ;\nd are accompanied by figure:- showing a [fit 
pi interpretation of the contour lines. A contour line repr 
juts an imaginary line on the ground (a contour) every pa 
If* which is at the same altitude above sea level. Such a Hn 
)uld he drawn at any altitude, but in practice only the con 
mrs st certain regular intervals of altitude are shown. Th¬ 
ine of the seacoast itself is a, contour, the datum or zero of alti 
Lde being mean sea level. The 20-foot contour would be th 
Lore line if the sea should rise 20 feet. Contour lines sho 
Tin heights of many points—such a* road corner?,, huiui 
surfaces of lakes, and bench .mark*—are also given on the 
in figures, which show altitudes to the nearest foot only, 
coordinates of fcriangulation stations, are published in bulk 
issued by the Geological Survey. 
Lettering and the works of man are shown in black. Bov 
aries, such as those of a State, county, city, land grant, tc 
e shape of the hills, mountains, and valleys, as well as theiri - ship, or reservation, are shuwja by continuous or broken 1 
ti t--i i r. n n/mnni trn nA ia i >• ll Tl An ill il f O T*A lr» Cl r\fl id AM tl i r4 r. f A•!I . ! . J - _ 3 _ — 2 i - - 4 * _ .1 __ -. 1. I * _ I 
Ititude. Successive contour lines that are far apart on 
Lap indicate a gentle slope; lines that are close together 
ite a steep slope; and lines that run together indicate a cj 
The manner in which contour lines express altitude, t 
id grade is shown In 
of different kinds ffiid .veighw Good muU>i 
The sketch represents a river valley that lies between U 
j In the foreground the sea, wltb a hs v that is pu 
J nclosed by a hooked sand bar. 
I . terrace into which small streams Lave cut narrow gu 
I he hill on the light has a rounded summit and geutlv s 
ib* 
STANDARD SYMBOLS 
CULTURE 
(printed in black) 
- A _ 
I 
Trail 
*■**•+ ■ 
Umlroads 
ELe^rtric 
l'oih'oad 
Tunnel 
Power 
tL* ansmis sio.n 
B^ealcs-recter 
aanij allies 
.Bridge TrswbndOas Jferrv 
(jxrini ufurtruA/n . 
and Stale line 
<3aunVr line Grvxl Township Eeservalion 
•ji* distri ct line. Bne 
Tanks and 
cril reservoirs 
o * 
QO and 
gas mdls 
1-due or 
quany 
Pi vi sped 
pi^rillage. or Small part or Jj.xangidadan V S.mraei-aJ 
t'dron$ i line oemcteTwliiiB point at* transit- moritnrieat 
traverse s tail cm 
Mine tunnel Mine, tnmidl l.ij 
Coast Guard 
station 
water 
I printed i»t blue) 
X 
-Aqueducts Sr 
Wtj lerjiipe s 
-Aqueduct 
txmtuAs 
Lake ra* 
pOIid 
IhenarVByed 
stream and 
abandoned oanuJ 
Streams 
