The Barre daily times. (Barre, Vt.) 1897-1959, 1911-12-11
NEW MAP OF NORTH AMERICA.
Forty-Two Colors Shown on Map of the
Continent Issued by Geological Survey.

The most notable map publication OF
the year is the large geologic map OF
North America just issued by the United
States Geological Survey. II represents
an exceptional type OF engraving and
photographic color work and is printed in
four sheets which fitted together and
mounted make map Q feet inches
high by feet wide, the largest piece OF
work ever issued by the survey. The
scale is to 100000, or so miles to the
inch, and the plan of projection is in
harmony with the universal world map
on scale of ! TO 100000, in that il
shows the units of publication OF the
world map, each Of which embraces four
degrees of latitude and six degrees OF
longitude.
Each Sheet Printed Fourteen Times.
The color scheme of the map is n
striking one. In all there are AZ dis-
tinetions, varying from a brilliant red
to pale tints approaching white. These
were produced by IA separate printings
from photographic stones, requiring in
many places two or three combinations
of color to produce the desired effects.
II the weight Of paper and heavy stones
lifted back and forth in the printing of
this job We're to be completed, it would
run into the hundreds of tons. The
accuracy of the register" or fitting
together of the color blocks in small
areas throughout the map, is remarkable.
The work was done in the surveys own
engraving and printing plant, and it is
believed that there are few If any other
establishments in the United States ca
pable OF turning out such a production.
The AZ color distinctions represent as
many divisions of rock strata. Thus the
rocks of seven divisions of the Paleozoic
era are each represented by color, be-
sides three separate colors for undiffer-
entiated rocks, and there are other colors
for the divisions of the Mesozoic, the
Tertiary, and the Quaternary.
The coloring of the map is both eff
fective and pleasing. The scheme is sys-
tematic in that the eolors range in pris.
matte order from yellow in the upper
portion of the geologic column through
greens, blues, and puppies to pinks and
browns at the base. The colors for the
igneous rocks, both plutonic and vol,
eanic, are mostly bright red. Viewed
as a wall map, the map Of North Amer
lea shows only the large geologic units.
as the smaller divisions are represented
by different shades and tints of the
same or closely allied colors, which are
indistinguishable at moderate distance.
Valuable for Detailed Study.
Viewed close at hand, these minor
distinctions can be read and the map can
be used for detailed study limited only
by the scale. When it is used as a wall
map, the regions illustrating different
types of geology stand out boldly. The
great Canadian shield of pro -Cambrian
rocks is represented by subdued color
in a pattern similating crystalline tex
tnre. Parallel bands of darker colors
from New Brunswick to Alabama mark
the trend of the Appalaehians, while the
broad area of blue and gray colors to the
west represent the coal fields of the in.
terror, and a fringe of yellow colors to
the east and south represents the coastal
plain sediments. A brilliant vermilion
eoloring over much of the western part
of the continent from Alaska to Central
America strikingly portrays the volcanic
activity in this region during the Ter
tiary period, and the broad area of green
and yellow in the middle West marks
the last stages of deposition of sediments
in the interior sea which covered that
part Of North American in Cretaceous
time and in the continental depressions
in Tertiary time, including many of the
great coal deposits of the public do.
main.
The map embodies all the available