The Barre daily times. (Barre, Vt.) 1897-1959, 1915-10-04
FOSSILS OF AID TO
THE COAL OPERATORS
Description of the Grand Mesa Coal
Field, Colorado, by the United
States Geological Survey.

Grand Mesa, Colorado, is great coal
bearing table-land rising about a mile
above the general level of the country
which lies to the south and west. The
West Elk mountains, near by, group of
peaks composed of igneous rock, rise
to altitude of over 10000 feet above the
sea level and together with Grand Mesa,
form some of the most sublime and inn
pressiue scenery to be found in America.
| Although now far above the sea level,
| this area was beneath the ocean for a
long time in the Cretaceous period, many
thousands of years before the advent
OF the first man. The sea was finally
filed with sediments, and great swamps
were formed, in which vegetable matter
accumulated as it is accumulated now in
Dismal Swamp. Some of the sediment
airy rocks containing the coal beds were
bowed up over the igneous rocks, which
are in the form of laccoliths, and Others
lie beneath them. The softer rocks near
the surface have since been eroded away,
and the laceoliths now stand as great
masses of rock, some of which are of
impressive proportions and beautifully
symmetrical in outline, and Others are
covered by erosion into picturesque and
fantastic forms.
Report by the United States Geological
Survey.
An interesting description of this area
is found in bulletin $40, by Willis I.
Lee, which can be obtained from the
United States geological survey. The
first part of the bulletin establishes the
geologic relations Of the coal. bearing
rocks, but the principal part is devoted
to a description OF the coal beds, their
number, occurrence. thickness. etc. The
largest producing mines are located at
Floresta, where anthracite is mined; at |
Crested Butte, where eoking bituminous !
coal is produced; and at Mount Carbon |
and Somerset, where the coal is non-cok- |
ing and bituminous. Ii is estimated that /
this region contains more than l6,00c,- /
100000 tons OF coal in beds that are
thick enough TO be of commercial value.
Fossil Animals and Plants Identify the
Goals.
The rock formations are described,
their appearance is illustrated by re-
production of photographs, and their
outlines are mapped so that the coal
bearing rocks can be readily recognized
IN the ground. In the greater part Of
he region the presence OF certain fos-
Ills indicates high-grade coal and the
presence Of certain others indicates low
yrade coal. For example, II the prospec-
or finds an oyster shell, like one figured
n this bulletin, in rocks near a coal
ed, or corbula which Is likely 70 be
Quad in shale just above a coal bed, he
nay be reasonably sure that his coal
vii prove to be- bituminous coal of a re-
atively high grade. But II he finds in
IN area OF undisturbed rocks certain
lam shells (Uniol or snail shells (Tulo-
oma and Campelomal or fossil leaves,
shich can be easily recognized by COM
airing them with the pictures given in .
he report. he may be reasonably GER !
ain that his coal is Of relatively low
rade and viii stick on exposure 20 the ,
ir. However. in areas where the rocks
ave been disturbed and the coal meta
lorphosed the fossils viii BE- Of little
- 70 the prospector, for in such areas
be Goals are all high grade