Catoctin clarion., 1911-06-08
GEOLOGICAL SURVEY MAP
READY FOR DISTRIBUTION.

m-nt topographic maps OF the En-
mitsburg and Taneytown quadrangl,s
surveyed in cooperation with the
States of Maryland and Pennsylvania
has Just been completed hy the United
States Geological Survey at Washing
ton, and the maps are available for
distribution. These maps represents
hy far the most complete survey ever
made of this section of the State. 1t
shows so clearly every physical fea-
ture Of the country covered that the
character of any part Of the quad
| rartslc, as well as the shapes and
areas of the hills and valleys, can be
seen at a glance. The elevation OF
any particular point in the entire
can he easily determined. This re-
lief of the country is graphically
>llown Ivy means of brown contour
;nrs, ach one Of which represents a
tain elevation above the sra-that
is, the Traveller following the course
hnwn hy one Of these contour lines
xill g. neither up hill nor down hill,
,ut ON level. The elevation indi
,ated hy every fifth line is shown by
figur on the map, and it is inter-
sting to determine the heights OF
different points, by simply counting
the contonrs up or down from one of
the marked lines. 1t is easy to un-
derstand how such map is of prime
value to the engineer who may be
laying out railroad or trolley route,
a highway, a drainage or irrigation
system, in fact, any piece of engineer
ing work. The water features OF the
neutrality-suspicious., lakes, etc.-are
shown in blue, with the same exact
ness of outline as the land features.
In addition to the topography, the
map shows, in black, all the works
of man-roads, principal bridges,
towns, houses, etc.
The topographic mapping done by
the Geological Survey represent the
highest type of geographic work, and
! the maps show substantially every
thing as it is on the ground at. the
time of survey. In making the sur
vey of this particular area, the top
ographcrs tramped over practically
every portion of the quadrangle,
hundreds of miles being thus covered.
Permanent iron bench marks, show
ing exact elevations, were also SIT at
various points in the quadrangle.
The location of these marks is' in
dicatcd accurately on the map, and
they can lie used for all time as the
basis for any further elevation. surveys
desired. This sort of map making
is very different undertaking from
that of constructing an avarage
geographical map, which is generally
a matter of mere approximation and
compilation. Everything on the
Geological Survey topogra phic sheet
is exact and true to nature.
This sheet forms but one small
section of,'great topographic atlas or
map OF the United States which the
Geological Survey is making, and
which, will be the largest and yet
most detailed map in the world. AL
ready nearly nineteen hundred OF
these sheets have been completed,
covering over third of the country.
In some parts of the country much
Of the work is carried through rough
and almost impossible areas, with
dense forests, insurmountable precip-
ices, or deep morasses. Hundreds
of temporary camps are made during
each field season, at attitudes rang
ing from above snow line to below
sea level. All this work is followed
by an enormous amount of office
drafting, and the task is finally COM
pleted in examples of coppcr-plate
engraving and lithogrphic printing
second to no others in the world.
The cost to the Government OF
these quadrangle surveys, for both
field and Office work, ranges from
4 SO, 500 to $1,000 each; but the maps
are sold at only the nominal cost OF
paper and printing 5 cents a copy or
SO a hundred. -
The Geological Survey will furnish
without charge index sheets showing
all the topographic maps which it
has published.