2014-10-10_PERMIT FILE - C1996083 ‎(3)‎

• Permit No: C1996083
• IBM Index Class Name: Permit File
• Doc Date: 10/10/2014
• Doc Name: Section 20
• Section_Exhibit Name: Volume VI Cultural Resources
• Media Type: D
• Archive: No

Mesaverde have also produced abundant remains of invertebrates including ammonite,
baculites, bivalves, and planktonic formanifera (Young 1955).
Rollins Sandstone
During most of Late Cretaceous time, northwestern Colorado was part of the interior
seaway. The marine Mancos Shale was deposited in this seaway. About 77 million years ago
(mya), the next to last regression of the seaway began. As the shoreline prograded erratically
to the southeast across northwestern Colorado, it left behind the shallow -marine to shoreface
blanket deposits presently known as the Castlegate, Sego, Corcoran, Cozzette, and Rollins
(also called Trout Creek) Sandstones. Behind these sandstones, the coals, mudstones, and
sandstones of the paludal (lower) part of the Mesaverde Formation were deposited in swamp,
lacustrine, and fluvial distributary channels.
The Rollins Sandstone is the lowest formation of the Mesaverde Group in the Paonia
area and sedimentation occurred in a shallow sea, near -shore environment. It is characterized
as a buff and light -grey fine- grained sandstone and grey shale. It is the thickest of the
shoreline blanket sandstones and varies from about forty to three hundred feet, with eastward
thinning (Cashion 1973). Contact with the underlying Mancos Shale is conformable.
Fresh water and marine fossils have been found in the formation, but it is unspecified as
to whether they are vertebrates or invertebrates (Fisher et al. 1959). Outcrops tend to weather
as white to tan massive sandstones; steep talus slopes of Mancos Shale often occur below
exposures. Because vertebrate fossils have not been directly reported from the formation, and
because of the steepness of its outcrops, the Rollins Sandstone holds little potential for the
occurrence of vertebrate fossil remains in the general area.
Lower Mesaverde (Coal Bearing Members)
The coal bearing members (upper and lower) of the Mesaverde formation are
stratigraphically between the Rollins sandstone and the barren member, with an approximate
700 ft. thickness completely present, except near the outcrop area. These members consist of
buff and grey fine- to medium - grained sandstone and grey shale. Coal occurs in minor
amounts in the upper part, but is considerably more abundant in the lower part. Thickness of
the formation varies in the area from 50 to 300 feet (Cashion 1973). Contact with the
underlying Rollins Sandstone is completely conformable. The sediments of the lower
Mesaverde member were deposited in the Late Cretaceous (77 mya) and represent regression
of the Cretaceous seas.
Fresh water and marine fossils have been found in the formation, but it is unspecified as
to whether they are vertebrates or invertebrates (Fisher et al. 1959). Outcrops tend to weather
as white to tan massive sandstones; steep talus slopes of Mancos Shale often occur below
exposures. Because vertebrate fossils have not been directly reported from the formation, and
because of the steepness of its outcrops, the Rollins Sandstone holds little potential for the
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