Bismarck daily tribune. [volume] (Bismarck, Dakota [N.D.]) 1881-1916, 1913-02-19
ADDRESS OF DR.. A. G. LEONARD,
STATE GEOLOGiST, BEFORE
N. o. SOC. OF ENGINEERS.

kOta cover an area of approximately
80, 900 square miles in the western
part of the state and the total tonnage
of workable coal has been estimated
at 500, 00O, 900, 900. No other state in
the Union has SO much coal as has
North Dakota. and few realize the
vastness of our resources in this valu'
able mineral.
The coal beds are confined to two
formations, namely, the Fort Union
and Lance. The Fort Union is one
Of the most important and best known
formations of the northwest. 1t Gov
ers a vast area east of the Rocky
Mountains, stretching from Wyoming
to the Arctic ocean in the valley OF
the Mackenzie river, including sever
al Canadian provinces, much of North
Dakota, eastern Montana, southwest
ern South Dakota and eastern Wyom.
ing.
The Fort Union IS a fresh water for
nation, the beds having been depos-
tied in a large lake or lakes, and is
composed of clay shales, alternating
with sa%ndstones, and containing many
beds OF Ignite. 1t is remarkably uni
form in color, composition and ap-
%pearance throughout the region. The
prevailing color is either a light ash
grey or yellow, but in places the beds
are almost white. The Fort Union
formation everywhere contains num-
erous beds Of Ignite coal.
The Lance formation has a wide
distribution in North Dakota and east
ern Montana, as well as in parts or
South Dakota and Wyoming. The
largest area in North Dakota is In
the s%outh-central part of the state.
A smaller area is found in the south
western corner of the state. In Nor
ton county this formation is found to
consist of three members; an upper
sandstone about 100 feet thick, a mid
die member composed of dark shales
with a few sandstone layers and hav-
ing a thickness Of 200 to ESQ feet, and.
a lower division made up of shales
and sa%ndstOnes in alternating layers.
This latter gnember has a thickness of
$50 feet or over, and the maximum
thickness of the entire Lance forma-
ton is not far from 700 feet in this
region.
In southern Billings county, partic-
ularly in the vicinity of Yule, and at
several points in Morton county,
workable beds Of Ignite are found in
the Lance formation, but throughout
most Of it's area the latter Is barren
of coal with the exception of thin
seams only a few inches thick. In
the Fort Union; formation, on the 9th
er hand, n rarely finds an outcrop
where several hundred feet of strata
are exposed that does not contain at
least one or more coal beds. These
range from top to bottom Of the for
nation, and do not appear to be con-
fined to an. any p%agtaiccu u lar horizon e Or Of, ho or
lions. ~
1t was formerly supposed that the lig-
mite beds were not of great extent
and covered but comparatively small
areas, one seam thinning out and be-
ing replaced by others at a different
horizon. But the detailed work OF
the past few years has shown that
some of the individual coal beds COW
er large areas. One, with a thickness
varying from 5,,to is feet, has a known
extent Of twenty miles in n direc-
ton and twenty-five in another, with
an area OF at least 500 square miles,
and probably much greater. Another
bed Of coal was traced 36 miles north
and south and "a miles east and west,
and while it's known area as shown
from outcrops< IS nearly 900 square
miles, it undoubtedly has an extent
of 1000 to 1900 square miles. This
coalbed, which has a thickness rang
ing from 8 to Is feet and over, has
been largely burned out or removed
by erosion, but still underlies a num-
Der of townships.
The Ignite coal beds Of the state
vary in thickness from less than an
inch to 50 feet, a bed Of the latter
thickness occurring On Sand creek, in
southern Billings county. Several
beds 20 feet thick are known, and
seams 6, s and 10 feet thick are com
mon.
During the past six or eight years
the North Dakota Geological Survey,
much of the time in cooperation with
the United States Geological Survey,
has studied in more or less detail the