Geologic formation (shale) in Montana, Wyoming, and other states
Benton Shale
Stratigraphic range: Cretaceous
Shale bluffs at Cow Island, Montana in the Missouri River Breaks adjoining Fort Benton, the type location of the Benton Shale. As seen in this image, the overlying Niobrara Formation is not as distinctive from the Benton Shale as in the lower plains and these shales were later reclassified as Colorado Shale. The Benton name was abandoned here in favor of subdivision as Belle Fourche Shale, Greenhorn Limestone, and Carlile Shale.
Type
Formation
Underlies
Niobrara Formation
Overlies
Dakota Sandstone
Lithology
Primary
Shale, chalky shale, chalk beds
Other
many bentonite seams, septarians, selenite, occasional sandstone
Location
Region
Montana, Wyoming, North Dakota, South Dakota, Colorado, Nebraska, Kansas
Country
United States
Type section
Named for
Fort Benton, Montana
Named by
Meek, F.B. and Hayden, F.V.
Year defined
1862
The Benton Shale (also Benton Formation or Benton Group) is a geologic formation name historically used in Montana, Wyoming, North Dakota, South Dakota, Colorado, Kansas, and Nebraska.[1] In the "mile high" plains in the center of the continent, the named layers preserve marine fossils from the Late Cretaceous Period. The term Benton Limestone has also been used to refer to the chalky portions of the strata, especially the beds of the strata presently classified as Greenhorn Limestone, particularly the Fencepost limestone.
The BentonShale (also Benton Formation or Benton Group) is a geologic formation name historically used in Montana, Wyoming, North Dakota, South Dakota...
Cretaceous BentonShale near Rock River, Wyoming. The Fort Benton Group, along with others in stratigraphic succession, was named after Fort Benton, Montana...
Niobrara Formation is overlain by the marine Pierre Shale and is underlain by the Carlile Shale or BentonShale. During the time of the deposition of the Niobrara...
same, then the formation may be called the "Lyons Sandstone," or the "BentonShale." When there are several different lithologies within the formation,...
entire time of the seaway; and, so, coupled with the Graneros Shale, the "old Benton" shales are the widest durable remnant of the Western Interior Seaway...
Great Plains of the North American Continent. They gave the name "Benton" to the great shale deposits between the sandstone bluffs at Dakota City, Nebraska...
sandstone), and an upper shale member. (The fourth member of the "Lower BentonShale" was the Mowry Shale.) The Thermopolis Shale was first named by geologist...
and Main Visitor Center (elevation 5,975 feet (1,821 m)) Golden Fault BentonShale Western Interior Seaway - During the Cretaceous Period this was the bottom...
geology of the Arkansas River in 1896, naming new units to replace the old BentonShale, acknowledged that the Timpas was already a local name for the limestone...
present in the Mancos Shale of the San Juan Basin, the Carlile Shale of the Denver Basin and Raton Basin, and the BentonShale of the North Park Basin...
land to submerge as the seaway opened. Shale and chalk were deposited over the area as Greenhorn of the Benton Group and the Niobrara Formation. Within...
Niobrara formations were called the Fort Benton formation or Benton Limestone. As noted, the greyish, chalky shale with great many thin limestones between...
classification below follows Benton 2004, and uses a synthesis of rank-based Linnaean taxonomy and also reflects evolutionary relationships. Benton included the Superclass...
limestone (equivalent to Wocklum Limestone) B – marly shale, including the Hangenberg Black Shale (HBS) at its base C – marly limestone (equivalent to...
goniopholidid mesoeucrocodylian. Fossils have been found from the Graneros Shale of the Benton Group in Wyoming, and are of Cenomanian age. It was slightly over...
Mountains. The shale can weather to buff color under hilltops. Exposures show many thin, rust-colored bentonite beds (named for the Old Benton Limestone classification...
Colorado. He described it as a medium gray shale, capped with limestone or sandstone, and assigned it to the Benton Group. By 1931, William Walden Rubey and...
Cambrian through Pennsylvanian sedimentary rocks. The Collier Shale, located at the core of the Benton-Broken Bow Uplift, is the oldest exposed formation of the...
of Estaingia bilobata and Redlichia takooensis from the Cambrian Emu Bay Shale (Australia), and their implications for inferring the course of moulting...
Harpoceras falcifer zones, of the Posidonia Shale. Additional materials were described by Hannah Caine and Michael J. Benton in 2011, from the early Toarcian Beacon...
phylogeny of this group is fairly well known. The following cladogram, based on Benton (2005), illustrates the concept: The crown group here is Neornithes, all...
intervals are exposed: the East Kirkton Limestone (oldest), Little Cliff Shale (middle), and Geikie Tuff (youngest). The East Kirkton Limestone in particular...
western North America; this formed the Mowry Sea, so named for the Mowry Shale, an organic-rich rock formation. In the south, the Gulf of Mexico was originally...
answer. American paleontologist Charles Walcott, who studied the Burgess Shale fauna, proposed that an interval of time, the "Lipalian", was not represented...
on a skull of a specimen of Plioplatecarpus from the Campanian Bearpaw Shale (Alberta, Canada) preserved with a sclerotic ring is published by Holmes...
Palaeopleurosaurus, which is known from the Early Jurassic (Toarcian) Posidonia Shale of Germany, as well as Pleurosaurus from the Late Jurassic of Germany and...
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