GEOLOGICAL SURVEY CIRCULAR 368 

FEATURES SHOWN ON 

TOPOGRAPHIC MAPS 

UNITED STATES DEPARTMENT OF THE INTERIOR 

Douglas McKay, Secretary 

GEOLOGICAL SURVEY 

W. E. Wrather, Director 

GEOLOGICAL SURVEY CIRCULAR 368 

FEATURES SHOWN ON TOPOGRAPHIC MAPS 

By John B. Rowland 

Washington, D. C., 1955 

Free on application to the Geological Survey, Washington 25, D. C. 

GEOLOGICAL SURVEY 

TOPOGRAPHIC INSTRUCTIONS 

Chapter 1 B 3 

FEATURES SHOWN ON TOPOGRAPHIC MAPS 

Contents 

Abstract .............. . 

Principles of map representation 

1. Definition of a n1ap • • 

a. Topographic map . . . . . . . . . 

b. Planimetric map ..... 

2. Elements of map construction . 

a. Colors and classes of features . . 

b. Lines and symbols . . .... 

c. Letters and numbers . . • . . 

d. Map scale . . . . . . . . . . . 

3.. Problem of selecting features . 

4. Selecting map features for a purpose 

5. Other factors in selecting map 

Page 

5 

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5 

6 

6 

6 

6 

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features. . . . . . . . 7 

a. Legibility . . . . . . 7 

b. Cost of production . . . . . 8 

c. Obsolescence . . . . . . . . . 8 

d. Concept of a landmark 8 

Map delineation of topographic relief 8 

6. Methods and objectives 8 

a. Measurement . . . . . . . . . 9 

b. Interpretation . . . . • . . . 9 

7. Selection in mapping relief features . 9 

a. Choosing a contour interval 9 

b. Generalization . . . . . . . . 10 

8. Topographic expression 10 

9. Kinds of relief features 10 

a. Erosional features . . . 

b. Residual features ... 

c. Depositional features . . 

10. Symbols and patterns used to show 

relief ....... . 

10 

12 

12 

12 

a. Hachures . . . . 12 

b. Area patterns . . 12 

c. Relief shading. . . . 15 

Map representation of water features . 15 

11. Periodic changes in water features . 15 

a. Classification of water features . 16 

b. "Normal" water level ...... . 16 

Page 

Map representation of water features--Continued 

12. Kinds of water features and map 

symbols . . . . . . . . . . 16 

a. Linear watercourses . . • . . . 16 

b. Area water features. . . . . . . 17 

c. Glaciers and permanent snowfields •....•. 

d. Springs and wells . 

e. Coastal features . • 

Manmade map features . . • 

13. Coordinate systems, subdivisions, 

and boundaries . . . • . . . 

a. Coordinate systems • • • • 

b. Public-land subdivisions 

c. Boundaries . . . . . • . . 

14. Travel and transportation routes . 

a. Roads and trails . • . 

b. Railroads .•..•... 

c. Other route features 

15. Buildings and cities .. 

a. B11ildings ..•.. 

b. Building groups . . 

c. Towns and cities 

16. Names, notes, and numbers • 

a. Map names . • • • . • . 

b. Geodetic control marks . 

c. Spot elevations •.... 

Information on map margins . • . 

17. Identification, orientation, and 

explanation . . . • . • . . 

a. Identification . . . . . . 

b. Responsibility, methods, and 

dates • . • . • . • ••• 

c. Scale, contour interval, and 

other data ..• 

Map references • . • . . . . . 

18. Special selected list . 

19. Other reference maps 

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Figure 1. 

2. 

3. 

4. 

5. 

6. 

7. 

8. 

9. 

10. 

Pictographic map symbols 

Comparison of map scales 

Illustrations 

Contours. . • . • • • . • . • . • .. 

Two maps of identical areas in southeast New York State •.• 

Con toured slopes • • . • • • • • • . . . • . • . 

Drumlins in northern New York .•. 

Cedar Creek alluvial fan in Montana . 

Depression contours and hachures .. 

Hydrographic features. • . • . • • • • . • • • . 

Information shown in center of lower margin. 

Topographic map symbols . . . . . . . . . . . . . . . . . 

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22 

facing page 22 
Chapter 1 B 3 1 

FEATURES SHOWN ON TOPOGRAPHIC MAPS 

ABSTRACT 

Topographic maps represent features on the earth's surface by 

means of symbols and labels; separate colors distinguish the main classes 

of map features. The amount of information shown on a topographic map 

depends on the map scale, the purpose of the map, and the cost of obtaining the information. This chapter describes the three main categories of 

map information and the methods by which they are shown. Reference 

lists of published maps and a chart illustrating standard map symbols are 

included. 

PRINCIPLES OF MAP REPRESENTATION 

1. Definition of a map 

A map is a graphical representation, at an 

established scale, of a part of the earth's surface, showing important natural and manmade 

features in their correct positions relative to a 

coordinate reference system and to each other. 

a. Topographic map. --A topographic map, 

as distinguished from other kinds, portrays by 

some means the shape and elevation of the terrain. Geological Survey topographic maps usually represent elevations and laNdforms--the 

shapes into which the earth's surface is sculptured by natural forces--by contour lines. Other 

features are shown by a variety of conventional 

signs, symbols, lines, and patterns, which are 

printed in appropriate colors and identified by 

names, labels, and numbers. The chart facing 

page 22 shows the standard symbols used on the 

topographic maps of the Survey. 

b. Planimetric map. --A planimetric map 

is similar to a topographic map, except that it 

does not portray relief in a measurable form. 

The Survey publishes some planimetric maps for 

use until they can be replaced by topographic maps. 

1

The number 1 B 3 signifies Book 1, Part B, Chapter 3 of the 

Geological Survey looseleaf manual of Topographic Instructions. For a table of contents, see Chapter 1 A 2 (Circular 92). 

2. Elements of map construction 

A topographic quadrangle map is the product of both engineering and the graphic arts. 

Surveys made on the ground and from photographs 

are organized in a coherent form and reproduced 

graphically according to a plan. To be useful 

the map must present information legibly. The 

graphic accuracy must be consistent with the 

accuracy of the source surveys and with the publication scale. The map must include the information essential to its purpose and must exclude 

nonessentials. The main -elements of quadrangle 

map construction have been formulated to attain 

these objectives. 

a. Colors and classes of features. --The 

information shown on the quadrangle map is 

divided into three general classes, each printed 

in a different color. Information about the shape 

of the land surface--hypsographic or topographic 

information--is printe'd in brown. Water features--hydrographic information--are shown in 

blue. Cultural features--manmade objects·--

are shown in black. The system of division is 

not precise. Some manmade features--for example, levees and earth dams--are also topographic features and are printed in brown, ·not 

black. 

5 
6 (Ch. 1 B 3) TOPOGRAPIDC INSTRUCTIONS 

Besides the colors used for the three main 

classes of features, green is used to show woodland--timber, brush, vineyards, and orchards--

and red is used to show public-land subdivisions 

(cultural features) and the classification of the 

more important roads. 

b. Lines and symbols. --Linear features 

are represented by lines of various weights and 

styles (solid, dashed, dotted, or some combinations). Structures, or individual features, are 

portrayed by a system of pictographs or symbols. 

The symbols originated as plan views of the objects they represent, and they retain something 

of this character although they are now formalized. The building symbol, for example, is a 

solid or open square. The railroad symbol is a 

line with evenly spaced cross ties. The dam and 

levee symbols look approximately like dams or 

levees as seen from the air. (See fig. 1. ) 

D j ( 

• • ////I I\\\'\.'\ 

II 

BUILDINGS DAM 

/ .... "''"''' ,,,,'' ,,,,,,, ~' ,,,, ,, 

'•, 

RAILROAD LEVEE 

Figure 1. --Pictographic map symbols. 

c. Letters and numbers. --Because lines 

and symbols cannot represent map information 

completely, they must be supplemented by the 

names of places and objects. Notes must be 

added to explain some features that cannot be 

depicted clearly by symbols alone. In mapping 

topographic features the information portrayed 

by contour lines must be supplemented by elevation figures. Letters and numbers are essential to map interpretation, but they tend to obscure other map information. Therefore, they 

must be selected and positioned carefully on the 

map so that interference with other detail is 

kept to a minimum. 

d. Map scale. --Map scale is the relationship of the size of the map to the size of the 

ground area it represents. The relationship 

may be expressed as a linear equivalent, such 

as 1 inch equals 1 mile--meaning that 1 inch 

measured on the map represents 1 mile on the 

ground--or it may be expressed in many other 

ways. The scale of Survey maps is given in the 

form of a ratio or fraction, without dimensions; 

the numerator is the distance on the map, and 

the denominator is the corresponding distance on 

the ground. For example, 1:24,000 means that 

one unit of length on the map represents 24,000 

similar units on the ground. 

3. Problem of selecting features 

The amount of information that can be depicted legibly on a map is limited by the scale 

of the map. The effect of scale on map content 

is emphasized if the scale is considered as a 

ratio of areas rather than a ratio of distances. 

Figure 2 illustrates the actual paper areas representing 1 square mile at 2 standard scales 

for topographic mapping. 

The major problem in map compilation is 

to make the best use of the available map space. 

The space cannot be crowded with lines and 

symbols beyond a definite limit without making 

the map unreadable, yet the amount of information that might be useful or desirable is almost 

unlimited. The cartographer must select the 

features that are the most valuable to the map 

user. The smaller the map scale, the more 

critical and difficult the problem of selection 

becomes. 

4. Selecting map features for a purpose 

Topographic maps are often made for a 

particular purpose. For example, a map made 
FEATURES SHOWN ON TOPOGRAPHIC MAPS (Ch. 1 B 3) 7 

I sq mi at 1=24 000 I sq mi at 1=62 500 

Figure 2. --Comparison of map scales. 

for the purpose of designing a new highway would 

show the type of woodland cover and the classification of soil and rock along the route. Information about drainage, property lines, and buildings 

would be shown in detail as required. The map 

would be in the shape of a strip and would cover 

a relatively small ground area. This type of map 

is called a special-purpose map because it has 

limited value for other uses. 

Unlike special-purpose maps, the quadrangle maps produced by the Geological Survey 

have been designed to be used for many purposes. 

Scales, contour intervals, accuracy specifications, and features that are shown on the maps 

have been developed gradually over a period of 

years to satisfy the requirements of governmental agencies, industry, and the general public. 

Because these maps serve a wide variety of 

uses--scientific, engineering, military, and administrative--they are called general-purpose 

maps. 

Changes in symbolization and in features 

to be shown are adopted only after careful consideration of their effect on the various map 

users, as well as the operational problems and 

costs involved in making the changes. Changes 

in symbolization usually are submitted to a governmental interagency Committee on Map Symbols for review and approval. 

5. Other factors in selecting map features 

The functions the map is intended to serve 

determine the features that it is desirable to 

map, but other factors must be taken into account before it is decided what features actually 

can be shown. Among the most important considerations are legibility, the cost of compiling 

the information, and the permanence of the mapped features. 

a. Legibility. --The requirement that map 

information be legible and easily read means 

that small map features must be represented 

by symbols larger than·the true scale size of 

the features. Roads, for example, are shown 

90 feet wide on 1:62, 500-scale maps despite the 

fact that most roads are not actually this wide. 

Buildings and other structures also are shown 

by minimum-size symbols that may be larger 

than the actual scale size of the buildings. On 

aerial photographs at the same scale as the map, 

which show all features at true scale size, small 

features sometimes are not visible without magnification. 
8 (Ch. 1 B 3) TOPOGRAPHIC INSTRUCTIONS 

Symbols larger than scale size take up 

extra map space; therefore, where small features 

are close together, all of them cannot be shown. 

Generally, the less important features are omitted in congested areas. 

b. Cost of production. --The extent to which 

some kinds of map features are shown is determined partly by the cost of compiling the information. Aerial photographs are the source of most 

map information, but features that cannot be 

identified on mapping photographs must be obtained by field methods, a procedure that is relatively more expensive. As an example, not all section corners are mapped; they are too small to be 

seen on aerial photographs, and the cost of mapping all of them by field surveys would be excessive. 

c. Obsolescence. --Not only the original 

cost but also the cost of keeping the map up to 

date is considered in deciding what features to 

map. Generally, the more features depicted, the 

more quickly the map becomes out of date. Cultural features are especially subject to change. 

If the maps are to have a reasonably long useful 

life, the features portrayed must be restricted, 

to some extent, to relatively permanent.objects. 

d. Concept of a landmark. --Many kinds of 

features are shown on some maps, although 

omitted from others, because of the landmark 

character of the features. In this sense, a landmark is an object of sufficient interest in relation 

to its surroundings to make it outstanding. For 

example, buildings may be considered landmarks 

when they are used as schools or churches or 

when they have some other public function. They 

may be landmarks also because of their outstanding size, height, or design; or they may be landmarks because of their history, such as old forts 

or the birthplaces of famous men. 

The same principle is applied to features 

other than buildings, but the adjacent area always 

is considered in relation to the object. Where 

map features are few, objects that would not be 

shown in more congested districts may be mapped as landmarks. 

MAP DELINEATION OF TOPOGRAPHIC 

RELIEF 

6. Methods and objectives 

Contour lines are the principal means used 

to show the shape and elevation of the land surface. Other means are spot elevations and 

hachures and pattern symbols for special kinds 

of relief features that are not suited to contouring. Relief information is printed in brown on 

topographic maps. 

Con tours are lines connecting points of 

equal elevation. They always are continuous 

lines, and, if the map is large enough, they return to the points of beginning to form closed 

loops. A contour may be variously defined as--

An imaginary line on the ground, every point 

of which is at the same elevation above 

a specified datum surface (mean sea 

level for topographic maps of the Survey). 

A level or grade line. 

A line of constant elevation. 

A coastline or shoreline of level water. 

An assumed shoreline resulting from the 

assumed rising of a body of level water. 

However it is defined, a contour is the 

line traced by the intersection of a level surface 

with the ground. A series of contours is traced 

by a series of level surfaces, a different contour 

for each elevation. Contours are illustrated in 

figure 3. Each contour line on the map represents a definite ground elevation measured from 

mean sea level, and the contour interval is the 

difference in elevation between adjacent contours. 

The contour interval, together with the spacing 

of the contour lines on the .map, indicates the 

slope of the ground. On steep slopes the lines 

are more closely spaced than on gentle slopes. 
FEATURES SHOWN ON TOPOGRAPHIC MAPS (Ch. 1 B 3) 9 

To make maps more readable, contours 

are classified and the classes distinguished by 

different weights and styles of lines. Index contours--every fourth or fifth contour, depending 

on the basic interval--are accentuated by making 

the line wider than the other contours. Supplementary contours, used on the flatter areas of 

some maps, are shown as dashed or dotted lines. 

Elevation figures are shown on the contour lines 

at frequent intervals to facilitate their identification, as well as to assist in determining the values 

of adjacent contours. 

The two main reasons for showing relief 

information on maps are to furnish coordinated 

data for engineering calculations or other scientific mensuration and to present a graphic picture 

of the ground surface. The two objectives are 

related but distinct, and sometimes they may be 

conflicting. 

a. Measurement. --For engineers or scientists who are interested in exact measurement, 

topographic maps furnish dimensional information 

about elevations, areas, grades, and volumes. 

The approximate elevation of any point can be 

read directly or interpolated from contours. A 

series of elevations on a line determines the grade 

or profile of the line, and areas and volumes can 

be computed by combining line profiles in various 

ways. The relief information shown by contours 

is sufficient for calculating the storage capacity 

of a reservoir, the area of a watershed, or the 

volume of earth to be moved in a large road cut 

or fill. 

b. Interpretation. --On the other hand, many 

persons who use maps are not concerned with 

exact ground elevations but are more interested 

in the general appearance and shape of the land. 

For them, contours are the graphic means of visualizing the terrain and an aid in locating positions 

on the map. 

7. Selection in mapping relief features 

The amount of relief information that can be 

shown on a map depends largely upon the scale of 

the map and the contour interval used to portray 

the relief. If a great amount of relief detail is required, the scale must be enlarged and the contour 

interval made smaller; but regardless of the scale 

Figure 3. --Contours. 

and contour interval all information concerning 

the ground surface cannot be shown on maps. 

The mapmaker must always make a judicious 

selection of the features that it is desirable to 

portray. 

a. Choosing a contour interval. 2 --A satis~ 

factory contour interval is one that shows the important topographic features adequately, yet does 

not result in closely spaced contour lines that ar~ 

difficult to read. For a given scale and contour 

interval, the slope of the ground determines the 

spacing of contours on the map. Therefore, the 

most appropriate contour interval is selected according to the scale and the average ground slope 

in the quadrangle. Most quadrangles in continental United States are mapped with intervals of 5, 

10, 20, 40, or 80 feet. 

2 See Chapter 1 B 2, Contour intervals. 
10 (Ch. 1 B 31 TOPOGRAPHIC INSTRUCTIONS 

Vvhere slopes vary considerably within a 

quadrangle, the interval chosen may not give 

enough information in flatter areas because the 

contours are too far apart. Where this occurs, 

supplementary contours--at one-half or onefourth of the basic interval--are added in the flat 

areas. If the interval based on average slope 

causes too much congestion of contours in the 

steeper areas, intermediate contours may be 

dropped for short distances to avoid coalescence 

in printing. This treatment in drafting or scribing is called ''feathering.'' 

The contour interval used determines not 

only the amount of relief information that can be 

shown but also the allowable tolerances in the 

vertical accuracy of the map. The two are directly related. 3 

b. Generalization. --Small irregularities 

of the ground surface are omitted from the map 

by drawing the contours as smooth lines through 

these areas. The technique of ignoring the very 

small features and drawing the contour lines so 

that the larger features are emphasized is called 

generalization. 

Generalization is used to some extent in 

contouring at any map scale, because it is obviously impossible, even at the largest scale, 

to show every irregularity of the ground surface. 

The amount of detail omitted varies inversely 

with the map scale; some of the relief detail 

mapped at the scale of 1:24,000 may be omitted 

at the scale of 1:62, 500. Figure 4 illustrates 

an area contoured at the scales of 1:24,000 and 

1:62, 500; the greater amount of detail shown at 

the larger scale is plainly evident. 

8. Topographic expression 

The drawing of contour lines on a map is 

both an art and a science. It is a science in the 

sense that the lines must be positioned within 

certain limitations of accuracy; it is an art in 

that within this limitation the mapmaker has a 

limited choice in the way the lines are drawn. 

When the contour lines are drawn so that they 

represent the typical characteristics of the 

ground surface, the map is said to have good 

topographic expression. On the other hand, the 

3 See Chapter 1 B 4, Accuracy specifications for topographic mapping. 

contours could be drawn to meet accuracy specifications and yet have such poor topographic expression that the map might give a misleading 

picture of the landscape. Good topographic expression makes the map easier to interpret--

that is, the relief features are easily identified. 

For example, the contours depicting a 

smooth, rolling hill, without abrupt breaks or 

sharp ridges, are drawn as a series of gently 

curved lines, with no acute angles. On the other 

hand, the contours portraying a rugged, kniferidged hill, with many cliffs, are jagged and 

bent sharply to indicate these characteristics. 

The amount of generalization and the accuracy 

may be the same for both features; the difference 

is in the detailed delineation of the contours. 

The contrast in contour treatment for two 

different kinds of terrain can be seen by comparing the smooth hills of New York in the 

Ticonderoga quadrangle with the rough, broken 

mountains of Wyoming in the Maverick Springs 

quadrangle. Both are ?!-minute maps at the 

scale of 1:24, 000, with 20-foot contour intervals. 

9. Kinds of relief features 

To illustrate the contoured appearance of 

different kinds of topographic features, examples 

from three general classes have been selected. 

a. Erosional features. --These features 

are formed by the erosive action of wind, waves, 

glaciers, and streams. Features formed by 

stream courses are the most common and include valleys, gullies, washes, and gorges. 

The typical contour characteristic of stream 

courses is the shape of the contour reentrant, 

the part of the contour. that curves or bends 

toward and away from the drainage channel. In 

a series of contours outlining a hill, reentrants 

show the courses of streams too small to be 

shown on the map with blue lines. The spacing 

between the reentrants along a stream shows 

the grade or slope of the watercourse. The 

shape of the reentrants sometimes suggests the 

steepness of the banks of the drain, or the kind 

of soil or rock formation through which the 

water flows. In flat areas the width of a stream 

channel often must be exaggerated to avoid 

running the contour lines together. 
FEATURES SHOWN ON TOPOGRAPHIC MAPS (Ch. 1B3) 11 

Figure 4. --Two maps of identical areas in southeast New York State. Each map 

covers 4 square miles. The upper one (1945) is at the scale of 1:24,000, 

with a contour interval of 10 feet; the lower one (1902) is at the scale of 

1:62,500, with a contour interval of 20 feet, 
12 (Ch. 1 B 3) TOPOGRAPIDC INSTRUCTIONS 

b. Residual features. --Features of this 

kind are the parts of the earth' s· crust that have 

resisted erosion effectively and have remained 

somewhat in their original state. Plateaus, 

benches, mesas, escarpments, cliffs, and terraces are typical residual features. Important 

characteristics of this class of features shown 

by contours are the slope and the breaks or 

changes in the slope. 

A slope may be uniform, concave, or convex. A uniform slope is indicated by even spacing of contours. On a concave slope, the contours 

are closely spaced near the top, gradually widening toward the bottom. On a convex slope, the 

arrangement is reversed; the contours are closely spaced near the bottom, and the spacing increases toward the top. Land slopes are seldom 

of a single type and may be found in all possible 

combinations. 

Rock escarpments, which usually border 

high flat plateaus, are characterized by closely 

spaced contours near the top, which bend sharply 

at the crest and meander across the plateau. The 

slope below the crest is usually concave, with 

the spacing between contours gradually increasing toward the base of the hill. Figure 5 illustrates contoured slopes; the Juanita Arch, Colo., 

7!-minute quadrangle is a good example of contoured cliffs, escarpments, mesas, and other 

residual features. 

c. Depositional features. --As the class 

name indicates, these features are deposits of 

soil, rock, and other material built up by such 

carrying agents as glaciers, streams, winds, 

and volcanoes. 

Drumlins, illustrated in figure 6, are 

elliptical hills of unstratified glacial debris, 

larger and steeper at the north end and tapering 

toward the south. Their contoured shape is typical and recognizable. Groups of drumlins occur 

in Wisconsin, New York, and Massachusetts. 

Eskers are another form of glacial debris, 

deposited in long, narrow bands by streams beneath glaciers. They vary in length from a few 

hundred yards to several miles; within an area 

they frequently occur in series. 

Alluvial fans develop in valleys at the base 

of block mountains, being formed from rock and 

gravel washed out of canyon mouths. They may 

be almost any size from a few feet to several 

miles in diameter. Usually, they slope evenly 

from the center to the outer edge, and their 

contoured appearance is that of a fan--hence 

the name. Figure 7 illustrates a typical alluvial 

fan in Montana. 

10. Symbols and patterns used to show relief 

Although contours are the best method of 

showing most topographic features, symbols 

must be used to represent features that cannot 

be shown clearly or economically by contours. 

Hachures and patterns are frequently used to depict relief in areas having a predominance of 

distinctive ground features that are either too 

intricate or too small to be individually or accurately shown at the scale or contour interval 

selected for the map. 

a. Hachures. --Hachures, short lines 

drawn in the direction of the ground slope, are 

used to show gravel or borrow pits too small to 

contour; piles of waste material, such as mine 

dumps (see fig. 8); small banks or escarpments 

that are prominent but not high enough to be 

shown by the selected contour interval; and similar relief features. 

A slightly different form of hachures is 

used to depict small earth dams, small levees, 

spoil banks, and cuts and fills along roads or 

railroads. Con toured depressions are distinguished from hills by short ticks at right angles 

to the contours, pointing toward the center of 

the depression. 

b. Area patterns. --Intricate surface areas 

too irregular to contour except in a very generalized manner, such as lava beds, sand dunes, and 

open strip mines, are shown by a variety of symbo1 patterns. The patterns are made up of dots, 

hachures, or form lines that indicate the typical 

appearance of the area. Where symbol patterns 

are used, no attempt is made to represent the 

topography in detail. The Medicine Lake, Calif., 

15-minute quadrangle shows a volcanic area with 

many craters and lava beds. The lava beds are 

represented by a surface pattern and generalized 

contours. 
FEATURES SHOWN ON TOPOGRAPHIC MAPS (Ch. 1 B 3) 13 

Figure 5. --Contou.red slopes. A flat-topped mesa in Wyoming mapped at the scale 

of 1:24, OCO, with a 20 -foot contour interval. The steep mesa rim is portrayed by closely spaced contours, which come together in places where 

there are vertical cliffs. Toward the foot of the hill the contour spacing 

is wider, indicating a generally concave slope. The outlined squares are 

public -land subdivisions 1 mile, more or less, between corners. Part of 

the North Butte, Wyo. , 7!- minute quadrangle. 
14 (Ch. 1 B 3) TOPOGRAPHIC INSTRUCTIONS 

Figure 6. --Drumlins in northern New York. The elliptical hills are oriented 

generally in the direction of glacial movement. Usually they are 

steeper at the north end. The map scale here is 1:24, 000; the contour interval is 10 feet. Part of the Sodus, N. Y., 7i- minute quadrangle. 
FEATURES SHOWN ON TOPOGRAPHIC MAPS (Ch. 1B3) 15 

Figure 7. --Cedar Creek alluvial fan in Montana. A deposit of sand and gravel 

washed out of Cedar Creek canyon in the mountains at the right. It 

forms a semicircular cone with a radius of almost 4 miles and with a 

height at the center of over 800 feet. The contoured slope is exceptionally uniform. The map scale here \S 1:62, 500; the contour interval is 

40 feet. Part of the Ennis, Mont. , 15- minute quadrangle. 

c. Relief shading. - -The pictorial effect of 

some maps is emphasized by relief shading, a 

half-tone overprint that simulates the appearance of sunlight and shadows on the terrain and 

provides the illusion of solid, three - dimensional 

topography. Relief shading copy is prepared 

after the rest of the map has been produced in 

the conventional way. Of the maps listed in 

article 18, the Delaware, Mich., the Ironton, 

Mo. , the Waldron, Ark. , and the Ennis, Mont. , 

15- minute quadrangles are published in shadedrelief editions. 

MAP REPRESENTATION OF WATER 

FEATURES 

11. Periodic changes in water features 

Unlike other natural features, most of 

which are reasonably stable, water features- -
16 (Ch. 1 B 3) TOPOGRAPHIC INSTRUCTIONS 

Figure 8. --Depression contours and hachures. Iron mines in the Mesabi district 

of Minnesota mapped at the scale of 1:24,000, with a 10-foot contour interval. Hachures show the piles of ore and waste material. Depression 

contours, with short right-angle ticks, show the open-pit mines. Many 

of the worked-out miries contain water. Part of the Virginia, Minn. , 

7~-minute quadrangle. 

shown in blue on the map--change from time to 

time. The levels of rivers, lakes, and reservoirs fluctuate during the year, according to the 

amount of rainfall and runoff. Smaller streams 

and springs may be entirely dry for a part of the 

year. Daily or even hourly variations in streamflow and water level occur in areas where melting snowfields or glaciers feed the streams or 

where streams are controlled for irrigation, or 

industrial purposes. 

a. Classification of water features. --To 

give a general indication of the amount of annual 

variation, water features are classified for map -

ping purposes as either intermittent or perennial. 

Intermittent streams, lakes, and ponds are those 

that usually are dry at least 6 months of the year. 

All others are perennial. 

b. ''Normal" water level. --The surface 

elevations and the shorelines of larger bodies of 

water usually undergo seasonal changes. As 

far as practical, the level shown on the map 

represents the so-called "normal" stage, defined as the one prevailing during the greater 

part of the year. Usually it corresponds to the 

line of permanent vegetation on the banks or 

shores. Strictly speaking, there is no normal 

stage; the definition is practical rather than 

precise. 

12. Kinds of water features and map symbols 

The style of lines, tints, and patterns 

shows the classification of water features as 

either intermittent or perennial. 

a . Linear watercourses. --Single lines 

represent rivers, streams, canals, and ditches 

less than 40 feet wide on 7i-minut~ maps, or 

less than 80 feet wide on 15-minute maps. If 

the features are larger than these dimensions, 
FEATURES SHOWN ON TOPOGRAPHIC MAPS (Ch. 1B3) 17 

shorelines are mapped to scale, and the spaces 

between the double lines are filled with blue tint 

(see fig. 9). 

Solid lines are used for perennial watercourses, either single - or double -lined. Intermittent drains are shown by dash-dot lines (long 

dashes separated by three dots). Falls and rapids 

in large streams are shown by hachures--in 

small streams by crossbars·. The Strasburg, 

Va., 15-minute quadrangle shows the falls and 

rapids in the South Fork of the Shenendoah River 

by blue hachures. 

b. Area water features. --All perennial 

open-water features are outlined in blue and 

filled with blue tint or blue half tone. Intermittent lakes and ponds are shown with dashed outlines and filled with a fine diagonal hatching. 

Marshes and swamps are shown with a characteristic pattern symbol; permanent stream channels 

passing through them are represented by solid 

lines. The Little Creek, Del., 7i- minute quad -

rangle map shows a large swamp containing 

many permanent stream channels. 

c. Glaciers and permanent snowfields. --

These are outlined with dashed lines and treated 

otherwise as relief features, except that the relief is shown in blue instead of brown. The relief and extent of these features may be indicated 

by regular contours, approximate contours (dashed lines), or by form lines. 

d. Springs and wells. --The landmark principle applies to the mapping of these water features. In arid regions where they are important, 

most of the springs and wells are shown; in humid 

areas, only the outstanding ones are mapped. A 

small circle with a tail pointing downstream symbolizes a spring. The well symbol is a small 

circle. 

e. Coastal features. --Quadrangles that 

include seacoasts and tidal waters sometimes 

show depth curves, soundings, some obstructions 

to navigation, and other marine detail of general 

interest. These maps are not intended, however, 

to be used as navigation charts. 

Depth curves are similar to contours, except that the interval is not necessarily constg.nt 

Figure 9. --Hydrographic fe atures. Map of 

part of the Pecos River in New Mexico, 

showing swamps, a sand bar, lakes, 

single-lined and double-lined streams, 

and intermittent and perennial streams. 

Scale 1:24, 000. Part of the Bottomless 

Lakes, N. Mex., 7i-minute quadrangle . 

and the reference datum is different. On the 

Atlantic Coast the datum is mean low water; on 

the Pacific Coast it is mean lower low water. 

The curves show the aver age water depth below 

the datum, in feet; they are not shown below a 

depth of 600 feet. Data for depth curves and 

soundings are taken from official hydrographic 

charts. 

Permanent fixed aids to navigation, such 

as lighthouses and beacons, are mapped, but 

nonfixed aids, such as lightships and buoys, are 

not shown. Obstacles to navigation--rocks, 

reefs, wrecks, and similar objects--generally 

are mapped if they are visible at low tide. 
18 (Ch. 1 B 3) TOPOGRAPHIC INSTRUCTIONS 

The shoreline along coasts is normally 

shown at the mean high-water line. Where 

swamps and marshes border the coast, the shoreline is shown at the outer limits of vegetation. 

Tidal flats are outlined with a dotted line, filled 

with a pattern and labeled. The Petit Manan, Me., 

7!-minute quadrangle is an example of coastal 

mapping, showing depth curves, reefs and rocks, 

with tidal flats portrayed by labeled surface patterns. 

MANMADE MAP FEATURES 

13. Coordinate systems, subdivisions, and 

boundaries 

Except for lettering, the lines representing 

political boundaries, land subdivisions, and coordinate systems are the only items of map information that are not physically evident on the 

ground. Boundary lines may be based on surveyed ground monuments, or they may be only described by statute. The lines of coordinate systems are mathematical abstractions. 

a. Coordinate systems. --Quadrangle maps 

show two systems of reference coordinates, the 

universal geodetic coordinates in terms of latitude and longitude and State plane coordinates. 

Parallels of latitude and meridians of longitude form the boundaries of standard quadrangles. 

Maps of continental United States at the scale of 

1:62, 500 measure 15 minutes in latitude and 15 

minutes in longitude, and maps at the scs.le of 

1:24,000 measure 7!-minutes on each side. The 

coordinates of the boundary lines are printed in 

the margins at each corner, and ticks are placed 

at intervals along each edge and within the body 

of the map--at 5-minute intervals on 15-minute 

maps and at 2!-minute intervals on 7!-minute 

maps. 

State plane-coordinate systems permit surveyors and others to use a simple reference grid 

and still base their work on the national net of 

geodetic control. Each State has an individual 

system, and most State systems have two or more 

zones. Within zones the coordinates of any point 

are the distances in feet north and east of an arbitrarily chosen zero point. 

Quadrangle maps show the State plane coordinates by labeled grid ticks along the border 

lines at 10, 000-foot intervals. If the mapped 

area lies in more than one zone, eacp zone is 

shown with a distinctive style of tick. The grid 

can be laid out on the map by drawing straight 

lines between corresponding ticks on opposite 

edges. 

b. Public-land subdivisions:--The surveyed lines that divide over two-thirds of the 

United States into mile-square sections form a 

cadastral grid system. The subdivision lines 

are property boundaries or the references for 

boundaries. Frequently they form in part the 

boundaries of political subdivisions, and in many 

areas the routes of public roads follow the subdivision lines. 

The subdivision lines and corners are 

shown on quadrangle maps to the extent that 

their positions can be determined from evidence 

recovered on the ground. "Found" subdivision 

corners are shown by he2.vy red crosses; lighter 

weight crosses are used for "indicated'' corners. 

Indicated corners are those marked in some 

manner, but not with markers set by the original 

surveyors. 

Subdivision lines accurately located are 

represented by solid red lines; dashed red lines 

are used where the location is uncertain. On 

maps published before about 1940, subdivision 

lines are shown by black dotted lines; on those 

published between about 1940 and about 1948, 

black solid lines were used. On modern maps 

dotted red lines sometimes are used to represent 

subdivision lines of an unofficial nature. 

Map represBntation of public-land subdivisions is not intended to be authoritative or official; it is presented as useful information, as 

accurately and completely as it can be at reasonable cost. In areas where a reasonable amount 

of field evidence cannot be found, the section 

lines are sometimes omitted. 

4 See Chapter 3 A 4, Mapping of public--land subdivisions. 
FEATURES SHOWN ON TOPOGRAPHIC MAPS (Ch. 1 B 3) 19 

c. Boundaries. --Boundaries of civil subdivisions are shown in black, using line weights 

and styles appropriate to the rank of the area, 

in the follov1ing order: 

National 

State or Territory 

County, parish, municipio, or judicial subdivision 

Civil township, town, district, precinct, 

barrio 

Incorporated city, village, town, borough, 

hamlet 

National or State reservation, park, or monument 

Small park, cemetery, airport, etc. 

The boundaries of less important areas are 

omitted where they are not well established or 

where they are subject to frequent change. Vlhere 

the boundaries of two civil units coincide, the symbol of the higher ranking unit -is used for the coincident part of the line. 

14. Travel and transportation routes 

Among the most important and generally 

useful items of map information are transportation routes. They are distinguished on the map 

by symbols and labels and are classified according to traffic capacity. 

a. Roads and trails. --The road classification system considers such factors as width, number of lanes, carrying capacity, and traffic restrictions. The symbols used to show different 

classes of roads are illustrated on the symbol 

chart. 

Federal highways are distinguished by 

shield symbols and State highways by circle symbols surrounding the route numbers. Permanent 

traffic restrictions are shown by notes. For important roads the distances to destinations outside 

the mapped area are shown in the margins. 

Unimproved roads and trails are mapped 

to the extent that the information is useful. In 

wilderness areas with few travel routes, most 

of the poorer roads and trails are shown; in 

more populated districts, some are omitted because they are less important and would congest 

the map. (See symbol chart.) 

b. Railroads. --Railroads are shown by a 

line-and-crosstie symbol and labeled with the 

name of the operating company. The number of 

tracks, if more than two, is shown by a label. 

Dismantled railroads are shown and labeled, 

and the roadbeds of abandoned railroads are 

shown, where they are landmark features, by 

· the trail symbol and labeled. 

Railroad yards are portrayed by a conventional track pattern, similar to the true pattern 

of the yard; the main tracks and the outlines 

are shown in correct position. The principal 

buildings are plotted to scale. (See symbol 

chart.) 

c. Other route features. --Other kinds of 

routes sometimes mapped include telephone 

lines, telegraph lines, powerlines, pipelines, 

aqueducts, and canals. Many of these, particularly powerlines and pipelines, are mapped as 

landmark features. The symbol is dropped as 

it approaches congested areas, or where it 

closely parallels more important linear features. 

Each type of route is shown by an appropriate 

line symbol and labeled if necessary for clarity. 

15. Buildings and cities 

Buildings and groups of buildings are by 

far the most common kind of map features. On 

quadrangle maps, all buildings cannot be shown 

legibly, and various means must be used to simplify the map representation. Some kinds of 

buildings are omitted, some buildings are shown 

larger than their true size, and in congested 

areas only landmark buildings are mapped. 

a. Buildings. --Two classes of buildings are 

distinguished on maps by symbol. Class 1, those. 

intended to shelter human activities, are shown 

by a solid or dot-filled symbol. Class 2, those 

intended for the protection of machinery, animals, 
20 (Ch. 1B3) TOPOGRAPIDC INSTRUCTIONS 

or materials, are shown with an open-outline or 

a hatched symbol. 

Minimum symbol dimensions are used for 

legibility even though the scale size of the building may be smaller. On 7-k-minute maps, class 1 

buildings up to 40 feet square and class 2 buiidings up to 60 feet square are represented by 

standard-size symbols. Larger buildings are 

mapped to scale. On 15-minute maps the minimum scale dimensions for the two kinds of symbols are 80 and 120 feet. Class 2 buildings 

smaller than the average dwelling, such as sheds 

and private garages, are not mapped. 

Churches are represented by the building 

symbol with a cross attached; schools, by the 

building symbol with a pennant attached. Names 

of churches and schools also are given if space 

permits. 

b. Building groups. --Sometimes the closely spaced buildings in a group, such as a tourist 

court or a college, cannot all be mapped in true 

position. The buildings outlining the group are 

shown, but some of the smaller buildings may be 

omitted and others displaced. Race tracks, drivein theaters, and other group structures are 

mapped in a similar way. The outlines are preserved, but the interior is simplified, showing 

only the more important parts of the feature. 

c. Towns and cities. --In urban areas, 

where the numerous buildings would congest the 

map, only the street pattern and landmark buildings are mapped. A pink-tint overprint denotes 

the area in which substantially all the building 

sites are occupied, but its limits may not coincide with the town or city limits. 

Landmark buildings that are mapped in 

urban areas include schools and churches; public 

buildings, such as post offices and railroad stations; and other buildings that are prominent because of their outstanding size, design, or historical associations. The small town of Virginia, 

Minn., for example, is shown on the 7!-minute 

quadrangle of that name by a pattern tint within 

which only the streets, railroads, and principal 

buildings are mapped. 

16. Names, notes, and numbers 

Topographic maps present a symbolized 

picture of the terrain, with features represented 

by lines, groups of lines, or conventional symbols. To make the picture complete and usable, 

names, labels, and numbers must be added. 

The lettering and figures must be placed on the 

map carefully so that they will be understandable 

and yet not obscure other map detail. 

a. Map names. --Names used on quadrangle 

maps are the names used by local people, as 

nearly as can be ascertained by field investigations. 

The Board on Geographic Names, a Federal agency, is the legal authority on names for 

government maps and other publications. In 

general, the Board's policy gives preference to 

local usage; where there is disagreement, the 

name in current use by the majority is preferred. 

Name information is obtained during field 

surveys from various sources, such as published maps, historical records, reference publications, and--most important of all--local residents. The information is crosschecked, and 

serious disagreements are referred to the Board 

on Geographic Names for decision. 

For buildings, dams, railroads, parks, 

and similar features, the names applied by the 

controlling organizations are used on the map. 

For natural features the names used by the majority of local residents are accepted. The number of names published depends on the map scale 

and the space available. Names are selected by 

the map editors, generally according to the relative importance of the features in the immediate 

areas. 

b. Geodetic control marks. --Although 

most of the permanently marked control survey 

stations are shown, a quadrangle map is not a 

control diagram because it may be necessary to 

omit some of the marks to avoid overcrowding 

the map. A complete record of the control surveys for a quadrangle area can be obtained from 

the Geological Survey, Map Information Office, 
FEATURES SHOWN ON TOPOGRAPIDC MAPS (Ch. 1 B 3) 21 

Washington 25, D. C., or from the Director, 

U. S. Coast and Geodetic Survey, Washington 25, 

D. C. 

Bench marks are symbolized by small 

crosses together with the letters "BM"; elevations 

are given to the nearest foot. Triangulation and 

transit traverse stations are shown with small 

triangles; elevations for these stations also are 

given if they have been determined. 

c. Spot elevations. --Spot elevations are 

established, during mapping surveys, for many 

points on the ground. These elevations are shown 

on the map as useful information at road forks, 

water surfaces, summits of passes, mountain 

tops, saddles, and other points of special interest. The ground location of a spot elevation may 

be clear from the surroundings, as at a road 

fork or on a sharp peak, or its position may be 

indicated by a small cross. Figures for checked 

elevations are printed in black and usually are 

reliable to within one-tenth of the contour interval. Figures for unchecked elevations are printed in brown. 

INFORMATION ON MAP MARGINS 

17. Identification, orientation, and explanation 

The space outside the neatline on published 

maps is used to identify and explain the map. The 

marginal information corresponds somewhat to 

the table of contents and introduction of a book--

it tells briefly how the map was made, where it 

is located, what organizations are responsible 

for the contents, and gives other information to 

make the map more useful. 

a. Identification. --In the upper right margin 

the quadrangle is identified by name, State, and 

series; the county name also is given if the area 

lies within one county. To locate the mapped 

JENKS QUADRANGLE 

OKLAHOMA-TULSA CO. 

7.5 MINUTE SERIES (TOPOGRAPHIC) 

area, the latitude and longitude of the quadrangle 

corners are given. The names of adjoining published maps are shown along each side and at each 

corner. On recent maps, a small diagram showR 

the approximate location of the quadrangle within the State. 

QUADRANGLE LOCATION 

b. Responsibility, methods, and dates.--

The organizations responsible for the map information are listed in the lower left margin. Here 

also are listed the principal methods of compilation, the dates of aerial photography and field 

surveys, the map projection used, the horizontal 

datum, the State plane aoordinate grid zones 

shown by ticks, and sometimes notes explaining 

the treatment of public-land subdivision or other 

features. 

Mapped, edited, and published by the Geological Survey 

Control by USGS, USC&GS, USCE, 

and Oklahoma Geodetic Survey 

Culture and drainage in part compiled from aerial photographs 

taken 1950. Topography by plane-table surveys 1951-1952 and 

in part by U. S. Corps of Engineers 

Polyconic projection. 1927 North American datum 

10,000-foot grid based on Oklahoma coordinate system, 

north zone 

Red tint indicates area in which only 

iandmark buildings are shown 

c. Scale, contour interval, and other data.--

The map scale is given in the center of the lower 

margin, both as a numerical ratio and as graphical bar scales in miles, feet, and kilometers. 

Below the bar scales are listed the contour interval and the vertical datum from which elevations 

are measured; for most maps the vertical datum 

is mean sea level. 

A map believed to be of standard accuracy 

carries a statement, printesl near the bottom of 

the lower margin, that the map complies with thE. 

National Map Accuracy Standards. If the map was 

published after 1948, absence of the accuracy 

statement means that in some respects the map 

probably does not comply with accuracy standard~. 

Before 1948, accuracy statements were not printed on the maps. Below the accuracy statement 

are given the addresses of the two main distribution centers of the Geological Survey from which 
22 (Ch. 1B3) TOPOGRAPHIC INSTRUCTIONS 

topographic maps may be purchased. Figure 10 

illustrates the information shown in the center of 

the lower margin. 

In the left lower margin an arrow symbol 

shows the approximate mean magnetic declination, 

APPROXIMATE MEAN 

DECLINATION, 1952 

east or west of true north, in the area for the 

year indicated. This information is taken from 

isogonic charts of the Coast and Geodetic Survey; 

it should be used with discretion because local 

magnetic attraction and annual variation affect 

the compass declination appreciably. In the 

lower right margin is a road classification legend. 

For the more important roads, destinations outside the mapped area with distances in miles from 

the map boundaries, are printed in the margins 

where the routes leave the map. 

Below the road legend, the names of the 

quadrangle and the State are repeated. Also 

given here are the coordinates of the southeast 

corner and the map series, an abbreviated form 

of identification. The date of the map information is shown at the bottom of the right margin. 

ROAD CLASSIFICATION 

Heavy-duty····- 4LAN£,6LAN£ Light-duty ·····--

Medium-duty~~ 4 LAN£ '

6 LAN£ Unimproved dirt======~ 

0 U.S. Route Q State Route 

JENKS, OKLA. 

N 3600-W9552.5/7.5 

1952 

MAP REFERENCES 

18. Special selected list 

The quadrangle maps Usted below have 

been selected to illustrate the characteristic 

topography of the five major physiographic regions of the United States. Those marked with 

an asterisk (*) are mentioned in this chapter as 

examples of particular kinds of map features. 

SCALE 1:24000 

1000 0 1000 2000 3000 4000 5000 

CONTOUR INTERVAL 10 FEET 

DOTTED LINES REPRESENT HALF-INTERVAL CONTOURS 

DATUM IS MEAN SEA LEVEL 

6000 

THIS MAP COMPLIES WITH NATIONAL MAP ACCURACY STANDARDS 

7000 FEET 

FOR SALE BY U.S. GEOLOGICAL SURVEY, FEDERAL CENTER, DENVER, COLORADO OR WASHINGTON 25, D. C. 

A FOLDER DESCRIBING TOP.OGRAPHIC MAPS AND SYMBOLS IS AVAILABLE ON REQUEST 

Figure 10. --Information shown in the center of the lower margin. 
TOPOGRAPHIC MAP SYMBOLS 

VARIATIONS WILL BE FOUND ON OLDER MAPS 

Hard surface, heavy duty road, four or more lanes ..... 

Hard surface, heavy duty road , two or three lanes .. 

Hard surface, medium duty road, four or more lanes .......... - - -

Hard surface, medium duty road, two or three lanes .. 

Improved light duty road .. 

Unimproved dirt road-Trai l .. 

Dual highway, dividing strip 25 feet or less .. 

Dual highway, dividing strip exceeding 25 feeL 

Road under construction .. 

Rai lroad: single track-multiple track .. 

Rai lroads in juxtaposition . 

Narrow gage: single track-multiple track .... 

Railroad in street-Carline ... 

;:::::::::d::::,::,;,d 

Tunnel: road-railroad .. 

•· ·•· ··••·• ••·•··•·•··•••···••··•·•··•·••·••••·••••••·••••·••·••· ·························· . ............ 

~======(== 

-+-------1

~ = = == E---+-

Overpass-Underpass .. 

Important small masonry or earth dam .. 

Dam with lock .. 

........................... ············· i :: II t= 

········· 0 

Dam with road .. H 

Canal with lock .. 

Buildings (dwelling, place of employment, etc.) ...... .• l dSII 

School-Church-Cemeteries .. ~t ~ : Cern : . ···························· • j -- ~ : ________ ~ 

Buildings (barn, warehouse, etc.) . ............. c=~· Power transmission line . 

Telephone line, pipeline, etc. (labeled as to type) .. .. ... ·--------

Wells other than water (labeled as to type) .. 

Tanks; oil, water, etc. (labeled as to type) .. 

Located or landmark object-Windmi ll 

Open pit, mine, or quarry-Prospect 

Shaft-Tunnel entrance . 

Horizontal and vertical control station: 

tablet, spirit level elevation .. 

other recoverable mark, spirit level elevation .. 

. ..................... .... cOil •....••... .o Gas 

.........• • e ®water 

.. .. 0 ... ...•••. 11 

....... ~ ... . ..•••• X 

.. ....... r! .. . 

BM8 3899 

83938 

Horizontal control station: tablet, vertical angle elevation ........ VABM82914 

any recoverable mark, vertical angle or checked elevation... 85675 

Vertical control station: tablet, spirit level elevation .. BM X 945 

other recoverable mark, spirit level elevation ... x 890 

Checkea spot elevation ... x 5923 

Unchecked spot elevation-Water elevati on .. .................. .................... x 5657 .....•. 8 70 

Boundary: national ..... . ................................................... ····················--___ _ 

state .... 

county, parish, municipio ... 

civil township, precinct, town, barrio ................. ······· - __ _ 

incorporated city, village, town, hamlet .................. ····---------- --

reservation, national or state .. 

small park, cemetery, airport, etc ... 

land grant 

Township or range line, U.S. land survey . 

Town ship or range line, approximate location .... 

Section line, U.S. land survey. 

Section line, approximate location ..... . ........... ······--------

Township line, not U.S. land survey .. 

Section line, not U.S. land survey . 

Section corner: found-indicated ...... ............................. + ....................... + 

Boundary monument: land grant-other ................................... a ............ a 

U.S. mineral or location monument . 

Index contour........... . ... ---------- Intermediate contour.. ----

Supplementary contour .. Depression contours .......... ~ 

Fill .. \ \1,, /JJ Cut ';fliil 

Levee ... 

Mine dump ... 

Tailings . 

Strip mine .... 

Sand area . 

Perennial streams ......... ~ Intermittent streams ..... ~.-:___-: :: 

Elevated aqueduct .. Aqueduct tunnel .............. -?======E--

Water well-Spring •••••··· .... <>-- Disappearing stream .. ·· ----------'-

Small rapids .. . . . . ~ Sma ll falls... . . ...... __________..... 

Large rapids . Large fa lls .............................. --- ,------, Intermittent lake .......... l ______ j Dry lake bed ........................ 07J§fZztD 

Foreshore flat... . . ~ Rock or coral reef. . . . .. ~ 

Sounding-Depth curve .. ~ 10 ~ Piling or dolphin 

Exposed wreck ... Sunken wreck .. 

Rock, bare or awash-dangerous to navigation ... * 

Marsh (swamp) .......... J" ,, ··'·· .. ,,.'''-fi Submerged marsh 

Wooded marsh ......... !.'"'_:'';,,_ <3 Mangrove 

Woods or brushwood ... .1 I Orchard ... 

Vineyard .I I Scrub. 

Inundation area .......... _______ _ House omission 
FEATURES SHOVJN ON TOPOGRAPHIC MAPS (Ch. 1 B 3) 23 

Quadrangle 

Ashby, Nebr., 

Bright Angel, Ariz. , 

Crater Lake National Park, Oreg., 

Delaware, Mich., (shaded relief) 

*Ennis, Mont., (shaded relief) 

Holy Cross, Colo., 

Ironton, Mo., (shaded relief) 

Jackson, Mich. , 

*Juanita Arch, Colo., 

Kingston, R. I. , 

Lake McBride, Kans., 

Mammoth Cave, Ky., 

*Maverick Spring, \t..Jyo., 

Menan Buttes, Idaho 

Mobile, Ala., 

Monadock, N. H. , 

Mt. Tom, Calif., 

Point Reyes, Calif. , 

Renova ·west, Pa., 

Sonoma Range, Nev. , 

*Strasburg, Va., 

*Ticonderoga, N. Y. -Vt., 

Voltaire, N. Dak. , 

*Vvaldron, Ark. , (shaded relief) 

Warm Springs, Ga., 

Scale 

1:62,500 

1:48,000 

1:62,500 

1:24,000 

1:62,500 

1:62,500 

1:62,500 

1:62, 500 

1:24,000 

1:62, 500 

1:24,000 

1:62, 500 

1:24,000 

1:24,000 

1:62,500 

1:62, 500 

1:62,500 

1:62,500 

1:62,500 

1:250,000 

1:62,500 

1:24,000 

1:24,000 

1:62,500 

1:62,500 

19. Other reference maps 

The following quadrangle maps are mentioned in the text as illustrating some particular 

types of features. 

Bottomless Lakes, N. 

Central City, Colo., 

Little Creek, Del., 

Medicine Lake, Calif., 

_North Butte, Wyo., 

Palmyra, N. Y., 

Petit Manan, Maine 

Sodus, N. Y., 

Mex., 

1:31,680 and 

Scale 

1:24,000 

1:62, 500 

1:24,000 

1:62,500 

1:24,000 

1:62,500 

1:24,000 

1:24,000 

!NT .-DUP. SEC., WASH., D.C. 79 615