60 THE UNITED STATES GEOLOGICAL SURVEY. [bull. 227. 
foresters will find them invaluable as a base for classifying the wood- 
lands and recording the nature and quantity of the various trees and 
the relation of the wooded areas to highways of transportation, as 
railways, streams, etc. These maps are, of course, essential to detailed 
geologic studies and to investigations concerning mineral resources, 
water power, and land reclamation. 
A good topographic map renders unnecessary a special survey for 
each new need. Prior to the existence of such maps every city was 
obliged to expend large sums in water-supply surveys. At far less 
cost the topographic map shows not only all these important local fea- 
tures, but also the relations between the artificial features in the imme- 
diate neighborhood and the topography and culture of the surrounding 
country, and thus broadens the scope of every such investigation. 
In 1884 cooperation in public surveys between the Federal and State 
governments was proposed by the State of Massachusetts. In the year 
mentioned the legislature of that State passed a resolution providing 
for "a topographical survey and map of the Commonwealth" in coop- 
eration with the United States Geological Survey, and appropriated 
the sum of $40,000 for carrying on the same. The Federal Survey 
allotted an equal sum to the work, and, in consultation with the State 
commissioners, agreed to make its surveys in the field on the larger 
scale of 2 inches to the mile, and to publish the results in separate atlas 
sheets having a scale of 1 : 62500, or about 1 mile to the inch, and with 
20-foot contours. Under this arrangement the survey of the State of 
Massachusetts was completed in 1888. In the same year, 1884, a some- 
what similar arrangement was made with the State of New Jersey, and 
the survey of that State was completed in 1887. In 1885 cooperation was 
arranged with the State of Rhode Island, and the survey of that State 
was completed in that year. In 1889 the cooperative survey of Con- 
necticut was commenced, and it was completed in 1891. At the present 
time cooperative topographic work is progressing in New York, Penn- 
sylvania, Ohio, West Virginia, Maryland, Maine, Kentucky, Alabama, 
Louisiana, Michigan, and California. 
The general plan adopted for mapping the United States consists in 
dividing the country into quadrilateral areas (called " quadrangles") 
bounded by parallels and meridians of latitude and longitude. Three 
regular scales and a series of special scales have been adopted. For 
reconnaissance maps in the rougher portions of the Far West and 
Alaska the scale of 1:250000, or nearly 4 miles to the inch, is standard. 
For the general map of the United States tho scale of 1:125000, or 
nearly 2 miles to the inch, is standard. In tho more densely popu- 
lated districts — the Atlantic coast, parts of tka Central region, and 
portions of the Pacific coast — the scale of 1:02500, or about 1 mile to 
the inch, is standard. These scales are readily convertible into the 
metric and other systems understood in foreign countries. However, 
