1981-11-13_PERMIT FILE - C1981013 ‎(28)‎

• Permit No: C1981013
• IBM Index Class Name: PERMIT FILE
• Doc Date: 11/13/1981
• Doc Name: Hydrology and Geology Information
• Section_Exhibit Name: Volume 1 Rule 2 Exhibit 6
• Media Type: D
• Archive: No

5
quartz sandstone 75 to 125 feet thick with dark gray, carbonaceous shale
locally present near the top of the unit. The Dakota Sandstone, also of
early Cretaceous age, rests disconformably on the Purgatoire. It is a
massive quartz sandstone, often exhibiting prominent crossbedding, with
thin interbedded shale. Its thickness in the study area is estimated at
50 to 200 feet. The Graneros Shale rests conformably on the Dakota. It
is a dark gray to black shale with an estimated thickness of 200 feet.
The Cretaceous Greenhorn Limestone intertongues with the underlying Graneros
and consists of 20 to 30 feet of dark gray limestone with minor amounts of
interbedded shale. The Carlile Shale rests conformably on the Greenhorn
Limestone and is composed of approximately 200 feet of dark gray shale that
includes thin sandstones and limestones near the top.
The Niobrara formation is upper Cretaceous and commonly divided into
the Fort Hays Limestone and Smoky Hill Marl members. The Fort Hays Lime-
stone rests conformably on the Carlile and consists of 20 to 30 feet of
grdy limestone and shale. The Smoky Hill member probably exceeds 700 feet
in thickness and is composed of white to buff limestone and marl .
The Pierre Shale consists of a dark gray to black marine shale con-
taining several thin zones of limestone as well as an upper sequence of
gray to black shale interbedded with buff to gray sandstone. The Pierre
has an estimated thickness of 1800 to 1900 feet in the study area.
i
The Trinidad formation is a light gray to buff, slightly arkosic sand-
stone that locally contains thin interbeds of shale. The formation inter-
tongues and is gradational with the underlying Pierre Shale. This fine to
very fine sandstone is often a cliff-former and has a thickness of approxi-
mately 250 feet in the study area.
The Vermejo formation conformably overlies the Trinidad. Typically,
the Vermejo is made up of three lithologies , buff, gray to gray-green,
slightly arkosic sandstone; gray to black carbonaceous shale; and coal .
The Vermejo thickens rapidly west of Cokedale to over 300 feet.
The Cretaceous-Paleocene, Raton formation constitutes the bedrock in
the study area. It rests unconformably on the Vermejo formation and