Hewitt Oil Field Zhe 
thicken rapidly toward the edges of the field and as the lower part of the 
anticlinal structure is reached. In the producing wells along the edge 
of the field, especially the south and west side, the Red Beds attain a 
thickness of 400 feet. The Permian thickens tremendously away from 
the field where the angular unconformity between the Permian and 
Pennsylvanian decreases. Many of the sandstones found in the Permian 
carry fresh water in considerable quantities. There is not a well de- 
fined basal water sand of the Permian in the Hewitt field as, in the 
Healdton field. (The Healdton Field, Oklahoma, by J. G. Bartram and 
Louis Roark. Bull. Am. Assoc. of Petroleum Geologists. Vol. 5.) 
Unconformity Below the Permain.—The Permain rests upon the un- 
derlying Pennsylvanian in the Hewitt field with an angular conformity. 
Beneath the Permian is a thick blue shale interval with occasional 
sandstone and thin limestone lenses, the former carrying gas, oil and 
water. This blue shale is of Pennsylvanian age and steeply dipping while 
the Permian on the surface shows only slight dips, therefore resting 
upon the Pennsylvanian with an angular unconformity. The Permian 
on the surface dips about 30 to 40 feet to the mile while the underlying 
Pennsylvanian shows dips of about 1,000 to 1,200 feet to the southwest. 
Pennsylvanian.—The Permian is underlain by a thick series of blue 
shale, sandy shale, sandstones and limestones of Pennsylvanian age, it is 
from these formations that the oil of the Hewitt field is produced. So far 
as known from present drilling records the Pennsylvanian varies in 
thickness from 1,200 to 2,200 feet in the Hewitt field and nowhere has 
the Pennsylvanian been drilled thru and older rocks penetrated. It is 
therefore impossible at the present writing to determine the thickness 
of the Pennsylvanian because of this lack of information, which can 
be obtained from deep wells penetrating the older rocks. The Pennsyl- 
vanian outcrops about 12 miles east of the Hewitt field where dips of 
65 to 85 degrees can be observed. It is also impossible to project these 
formations and estimate the thickness of the Pennsylvanian in the 
Hewitt field because of the angular unconformity between the Penn- 
sylvanian and the older formations below and the unconformity of the 
Pennsylvanian with the Permian above. In addition to these uncon- 
formities the Pennsylvanian formations have flattened out until they are 
dipping only about 10 to 12 degrees on the sides of the Hewitt field. 
The writer has not been able to accurately determine to which part 
of the Pennsylvanian these shales, sandstones and limestones belong, 
but believes they belong to the lower Pennsylvanian or Glenn formation. 
Beneath the Permian Red Beds there is a thickness of 1,000 to 1,800 
feet of blue shale with sandstone and limestone lenses. These irregular 
sandstone lentils carry water, oil and gas and occasionally make small 
gas and oil wells. Immediately under this shale interval is the main 
body of oil and gas sands called the Hewitt Sand Zone. The thickness 
of this zone has not been fully determined but is about 600 to 700 feet 
thick, carrying one to seven sandstones interbedded with shale, sandy 
shale and limestone. 
The lower Pennsylvanian has not been definitely identified in the 
Hewitt field due to either its absence or the fact that the wells have not 
