The Grand Hogback is a 70-mile long, curving, spine-like ridge in Western

Colorado Colorado (, other variants) is a state in the 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 western edge of t ...

that extends from near

McClure Pass McClure Pass is a mountain pass in the Rocky Mountains of western Colorado in the United States. It is located along the boundary between Pitkin and Gunnison counties, in a gap at the western side of the Elk Mountains. The pass is at an elevat ...

Pitkin County Pitkin County is a county in the U.S. state of Colorado. As of the 2020 census, the population was 17,358. The county seat and largest city is Aspen. The county is named for Colorado Governor Frederick Walker Pitkin. Pitkin County has the sev ...

through Garfield County and then to near Meeker in Rio Blanco County. The hogback is significant because it marks part of the boundary between the

Colorado Plateau The Colorado Plateau, also known as the Colorado Plateau Province, is a physiographic and desert region of the Intermontane Plateaus, roughly centered on the Four Corners region of the southwestern United States. This province covers an area of ...

to the west and the

Southern Rocky Mountains The Southern Rocky Mountains are a major subregion of the Rocky Mountains of North America located in the southeastern portion of the U.S. state of Wyoming, the central and western portions of Colorado, the northern portion of New Mexico, and ex ...

to the east.Colorado Mountain College
The Grand Hogback: Living life on the edge
Retrieved: March 27, 2017. The elevation of the ridge ranges from to . The hogback appears as a series of serrated ridges and is easily discernable from Google Maps and other aerial views. It is visible from

Interstate 70 Interstate 70 (I-70) is a major east–west Interstate Highway System, Interstate Highway in the United States that runs from Interstate 15, I-15 near Cove Fort, Utah, to a park and ride lot just east of Interstate 695 (Maryland), I-695 in ...

Gaps

Rivers have carved out several gaps in the hogback, the most notable being the one the

Colorado River The Colorado River ( es, Río Colorado) is one of the principal rivers (along with the Rio Grande) in the Southwestern United States and northern Mexico. The river drains an expansive, arid drainage basin, watershed that encompasses parts of ...

has carved out near

New Castle, Colorado The Town of New Castle is a home rule municipality in Garfield County, Colorado, United States. The population was 4,518 at the 2010 census, up from 1,984 at the 2000 census. History When New Castle was incorporated in 1888, its economy was ...

. Others include Harvey Gap and Rifle Gap,Colorado Parks & Wildlife
Rifle Gap
. Retrieved: March 27, 2017. both of which have been dammed to create reservoirs and state parks.

Geology

monocline A monocline (or, rarely, a monoform) is a step-like fold in rock strata consisting of a zone of steeper dip within an otherwise horizontal or gently-dipping sequence. Formation Monoclines may be formed in several different ways (see diagram) * ...

, the Grand Hogback is part of the

Mesaverde Formation The Mesaverde Group is a Late Cretaceous stratigraphic group found in areas of Colorado, New Mexico, Utah, and Wyoming, in the Western United States. History The Mesaverde Formation was first described by W.H.Holmes in 1877 during the Hayden ...

. The ridge formed towards the end of the

Laramide orogeny The Laramide orogeny was a time period of mountain building in western North America, which started in the Late Cretaceous, 70 to 80 million years ago, and ended 35 to 55 million years ago. The exact duration and ages of beginning and end of the o ...

during the middle to late

Eocene The Eocene ( ) Epoch is a geological epoch (geology), epoch that lasted from about 56 to 33.9 million years ago (mya). It is the second epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name ''Eocene' ...

References

External links

* The Geology of the Grand Hogback Monocline near Meeker, Colorado – Colorado Geological Survey. {{Authority control Ridges of Colorado Geology of the Rocky Mountains Landforms of Garfield County, Colorado Landforms of Rio Blanco County, Colorado Landforms of Pitkin County, Colorado