The Glenwood post., 1923-10-11

ABOUT $500 feet timex. Inc greater
part Of it is an almost homogeneous
mass of marine shale, which when
but when moist, as it is when it is
taken from a drilling well, is dark
gray or blush gray. A dark platy
shale, IT'S to 200 feet thick, which con-
tains an abundance of scales and other
remains of fish, occurs in the basal
part of the formation. This fish-scale-
bearing member may correspond to the
Mowry shale, which yields oil at sew
eral places in Wyoming. At one place
in Moffat county oil was found in
joints and between the laminae of this
fish scale-bearing member Above this
member is sandy zone which at some
places includes a bed of sandstone. 1t
has been suggested that this zone cor
responds to the Frontier formation,
which is the most productive oil-bear-
ing formation in Wyoming.
In the vicinity of the Hamilton and
the Seeping Spring Gulch domes a
thick lens of sandstone (the Morapos
sandstone member of unpublished re-
port by r. Il. Hancock lies about 800
feet below the top of the Mancos
shale. This sandstone, which forms a
conspicuous escarpment, has been re-
| moved by erosion from the crests Of
Al H.,
cos shale lies the Dakota sandstone,
| also of Upper Cretaceous age. This
sandstone, where it was observed at
various outcrops in Moffat county,
ranges in thickness from 17O to $50
| feet. Its lowest member consists of
black ebert pebble conglomerate and
is a somewhat variable ledge of thin
sandstone, with which is associated a
clayey shale that is at many places
greenish or purplish. The uppermost
member of the Dakota includes white
sugary sandstone, quartzite, and con-
clomeratic sandstone. At some places
Dakota sandstone is heavily saturated
with oil.
The Mancos shale and the Dakota
sandstone are the formations that are
nose likely to yield oil in the Hamil-
ton and Seeping Springs Gulch domes,
but oil may possibly occur in the Mug
get sandstone, of Jurassic age, which
can be reached by very deep drilling.
Immediately upon the Mancos shale,
covering parts of the flanks of she
Hamilton and Seeping Spring Gulch
domes, lie the strata of the Mesaverde
group Upper Cretaceous) which in
this region have been divided by Han
cock INTO the lies formation, compr1-.
ing the basal 1850 feet of Mesaverde
beds, and the Williams Fork forma-
tion, which is about l,6O0 feet thick
Both these formations contain alter
mating beds of sandstone and shale
and some coal. The thickest beds of
coal, however, are in the Williams
Fork formation, and this fact is Of
interest to the oil operator, for this
coal S an easily accessible and almost
ineXhaustible source of fuel.
The Hamilton dome is in the south
central part of T. 5 N, R. 81 W., and
the north-central part of T. N, R.
81 w. The town of Craig, which is
the terminous of the Denver and Salt
Lake railroad is about 13 miles dis
tant from the dome by auto road
Water for drilling can probably be had
from either Morapos creek or Williams
Fork by a pipe line to A miles long.
The coal beds of the Mesaverde forma-
tion are easily accessible.
The Hamilton dome has closure of
about 800 feet 1t is on the south end
Of the long Williams Fork anticline,
and appears to be by far the most