The Book Cliffs are a series of desert mountains and

cliff In geography and geology, a cliff is an area of rock which has a general angle defined by the vertical, or nearly vertical. Cliffs are formed by the processes of weathering and erosion, with the effect of gravity. Cliffs are common on co ...

s in western

Colorado Colorado (, other variants) is a state in the Mountain states, Mountain West subregion of the Western United States. It encompasses most of the Southern Rocky Mountains, as well as the northeastern portion of the Colorado Plateau and the wes ...

and eastern

Utah Utah ( , ) is a state in the Mountain West subregion of the Western United States. Utah is a landlocked U.S. state bordered to its east by Colorado, to its northeast by Wyoming, to its north by Idaho, to its south by Arizona, and to it ...

in the western United States. They are so named because the cliffs of

Cretaceous The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of ...

sandstone Sandstone is a clastic sedimentary rock composed mainly of sand-sized (0.0625 to 2 mm) silicate grains. Sandstones comprise about 20–25% of all sedimentary rocks. Most sandstone is composed of quartz or feldspar (both silicates ...

that cap many of the south-facing

butte __NOTOC__ In geomorphology, a butte () is an isolated hill with steep, often vertical sides and a small, relatively flat top; buttes are smaller landforms than mesas, plateaus, and tablelands. The word ''butte'' comes from a French word me ...

s appear similar to a shelf of books.

Stratigraphy

The Book Cliffs are one of the world's best places to study

sequence stratigraphy Sequence stratigraphy is a branch of geology, specifically a branch of stratigraphy, that attempts to discern and understand historic geology through time by subdividing and linking sedimentary deposits into unconformity bounded units on a variety ...

. In the 1980s, Exxon scientists used the

strata of the Book Cliffs to develop the science of

. The Book Cliffs have preserved excellent strata of the foreland basin of the ancient

Western Interior Seaway The Western Interior Seaway (also called the Cretaceous Seaway, the Niobraran Sea, the North American Inland Sea, and the Western Interior Sea) was a large inland sea that split the continent of North America into two landmasses. The ancient sea ...

that stretched north from the

Gulf of Mexico The Gulf of Mexico ( es, Golfo de México) is an ocean basin and a marginal sea of the Atlantic Ocean, largely surrounded by the North American continent. It is bounded on the northeast, north and northwest by the Gulf Coast of the United ...

to the

Yukon Yukon (; ; formerly called Yukon Territory and also referred to as the Yukon) is the smallest and westernmost of Canada's three territories. It also is the second-least populated province or territory in Canada, with a population of 43,964 as ...

in the Cretaceous Period. Components of deltaic and shallow marine reservoirs are very well preserved in the Book Cliffs.

Wildlife

Large mammals found in the Book Cliffs include

coyotes The coyote (''Canis latrans'') is a species of canine native to North America. It is smaller than its close relative, the wolf, and slightly smaller than the closely related eastern wolf and red wolf. It fills much of the same ecological nich ...

mountain lion The cougar (''Puma concolor'') is a large cat native to the Americas. Its range spans from the Canadian Yukon to the southern Andes in South America and is the most widespread of any large wild terrestrial mammal in the Western Hemisphere. ...

s, bobcats,

mule deer The mule deer (''Odocoileus hemionus'') is a deer indigenous to western North America; it is named for its ears, which are large like those of the mule. Two subspecies of mule deer are grouped into the black-tailed deer. Unlike the related whi ...

, elk, black bears,

pronghorn The pronghorn (, ) (''Antilocapra americana'') is a species of artiodactyl (even-toed, hoofed) mammal indigenous to interior western and central North America. Though not an antelope, it is known colloquially in North America as the American a ...

American bison The American bison (''Bison bison'') is a species of bison native to North America. Sometimes colloquially referred to as American buffalo or simply Bubalina, buffalo (a different clade of bovine), it is one of two extant species of bison, alongs ...

as an extension of the

Henry Mountains bison herd The Henry Mountains bison herd, numbering 250 to 400 bison, is one of only four free-roaming and genetically-pure herds on public lands in North America. The other three herds are the Yellowstone Park bison herd which was the ancestral herd for th ...

and

bighorn sheep The bighorn sheep (''Ovis canadensis'') is a species of sheep native to North America. It is named for its large horns. A pair of horns might weigh up to ; the sheep typically weigh up to . Recent genetic testing indicates three distinct subspec ...

. There are also many small streams that contain a variety of trout species. In January, 2009,

Utah Division of Wildlife Resources The Utah Division of Wildlife Resources is part of the Utah Department of Natural Resources for the state of Utah in the United States. The mission of the Division of Wildlife Resources is to serve the people of Utah as trustee and guardian of ...

officials transplanted 31 bison from the

Henry Mountains The Henry Mountains is a mountain range located in the southeastern portion of the U.S. state of Utah that runs in a generally north-south direction, extending over a distance of about . They were named by Almon Thompson in honor of Joseph Henry ...

bison herd to the Book Cliffs. The new group joined 14 animals previously released in August, 2008 from a private herd on the nearby

Uintah and Ouray Indian Reservation The Uintah and Ouray Indian Reservation (, ) is located in northeastern Utah, United States. It is the homeland of the Ute Indian Tribe ( Ute dialect: Núuchi-u), and is the largest of three Indian reservations inhabited by members of the Ute Trib ...

. Since this herd is located approximately north of the Henry Mountains, across mostly harsh, desert terrain, it should perhaps be considered as a separate herd, the Book Cliffs bison herd.

References

External links

*
Cretaceous Paleogeography - Showing Western Interior Seaway

The Soils of Western Colorado Mesa, Delta and Montrose Counties
{{authority control Cliffs of the United States Mountains of Colorado Mountains of Utah Colorado Plateau Mountains of Carbon County, Utah Mountains of Emery County, Utah Mountains of Garfield County, Colorado Mountains of Grand County, Utah Mountains of Mesa County, Colorado Stratigraphy of Colorado Stratigraphy of Utah Bureau of Land Management areas in Colorado Bureau of Land Management areas in Utah

Stratigraphy

Wildlife

See also

References

External links