The Pine Valley Mountains are a

mountain range A mountain range or hill range is a series of mountains or hills arranged in a line and connected by high ground. A mountain system or mountain belt is a group of mountain ranges with similarity in form, structure, and alignment that have ari ...

in Washington County,

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 its ...

, United States, spanning the county north of the city of St. George. The highest point in the range is Signal Peak at . The mountains are part of

Dixie National Forest Dixie National Forest is a United States National Forest in Utah with headquarters in Cedar City. It occupies almost two million acres (8,000 km²) and stretches for about across southern Utah. The largest national forest in Utah, it st ...

and are bordered to the south by the

Red Cliffs National Conservation Area The Red Cliffs National Conservation Area is a National Conservation Area located in southwest Utah, north of St. George at the northeasternmost edge of the Mojave Desert. It is managed by the Bureau of Land Management as part of the National La ...

Geology

The Pine Valley Mountains formed from the Pine Valley Laccolith, the largest

laccolith A laccolith is a body of intrusive rock with a dome-shaped upper surface and a level base, fed by a conduit from below. A laccolith forms when magma (molten rock) rising through the Earth's crust begins to spread out horizontally, prying apar ...

in the United States and perhaps the world. The laccolith was formed during a 20 million-year period of volcanic activity. After 4-5,000 feet of volcanic deposited on the Claron Formation, the magma vents were effectively sealed off. A final surge of magma, unable to find its way to the surface, pushed sideways along the weak seam between the Claron and the overlying volcanic layers. This injected a 3,000 foot-thick layer of

monzonite Monzonite is an igneous intrusive rock, formed by slow cooling of underground magma that has a moderate silica content and is enriched in alkali metal oxides. Monzonite is composed mostly of plagioclase and alkali feldspar. Syenodiorite is an o ...

porphyry to form the Pine Valley laccolith. The contact between the top of the Claron and the bottom of the laccolith can be seen in several locations, most notably near the headwaters of Cottonwood Creek along the southwest corner of the mountain range (see photo below in the gallery), and at the headwaters of Leap Creek north of the Browse Guard Station. After erosion exposed the laccolith, volcanic activity continued and the youngest flows are 1-1.6 million years old. Many volcanic cinder cones can still be seen in the foothills of the Pine Valley Mountains and these have been dated at around 20,000 years old. As a result of these lava flows, the valley for which the mountain range is named and in which the town of Pine Valley is situated, was formed when lava dammed off the Santa Clara River and formed a lake. Sediments eventually filled the lake until they reached the height of the lava dam. These sediments form the floor of the present day Pine Valley, Grass Valley, and Grassy Flat. The mountains straddle the divide between the

Great Basin The Great Basin is the largest area of contiguous endorheic watersheds, those with no outlets, in North America. It spans nearly all of Nevada, much of Utah, and portions of California, Idaho, Oregon, Wyoming, and Baja California. It is noted fo ...

watershed and the watershed of the

Virgin River The Virgin River is a tributary of the Colorado River in the U.S. states of Utah, Nevada, and Arizona. The river is about long.Calculated with Google Maps and Google Earth It was designated Utah's first wild and scenic river in 2009, during the ...

, a tributary of 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 watershed that encompasses parts of seven U.S. s ...

. The Chinamen's Canal tunnel at the north end of Grass Valley diverts the waters of Mill Canyon Creek from the Colorado River drainage system into the Great Basin drainage system, eventually finding its way into the Newcastle Reservoir via Pinto Creek.

Zion National Park Zion National Park is an American national park located in southwestern Utah near the town of Springdale. Located at the junction of the Colorado Plateau, Great Basin, and Mojave Desert regions, the park has a unique geography and a variety of ...

can be seen to the east from the mountains.

Wilderness

Part of the range is in the

Pine Valley Mountain Wilderness Pine Valley Mountain Wilderness is a wilderness area located in the Dixie National Forest in the U.S. state of Utah. It is the fourth-largest wilderness area located entirely within the state (following the High Uintas Wilderness, Zion Wildern ...

, which at is the fourth largest wilderness in Utah. The Cottonwood Forest Wilderness is located at the southeastern end of the range.

Flora and fauna

The Pine Valley Mountains support spruce-fir forests, including a large stand of virgin

Engelmann spruce ''Picea engelmannii'', with the common names Engelmann spruce, white spruce, mountain spruce, and silver spruce, is a species of spruce native to western North America. It is mostly a high-altitude mountain tree but also appears in watered canyon ...

. The mountains also have numerous meadows up to in size. Several threatened, endangered, and sensitive species live in the mountains, including Bonneville cutthroat trout,

Townsend's big-eared bat Townsend's big-eared bat (''Corynorhinus townsendii'') is a species of vesper bat. Description Townsend's big-eared bat is a medium-sized bat (7-12 g)

, and the

pygmy rabbit The pygmy rabbit (''Brachylagus idahoensis'') is a rabbit species native to the United States. It is also the only native rabbit species in North America to dig its own burrow. The pygmy rabbit differs significantly from species within either ...

, among others. Botanically speaking, Pine Valley Mountain is the most diverse mountain range in Utah. A floristic survey was conducted between 1985 and 1987 and 967 species were collected. Since then, additional species have been added bringing the total to nearly 1,000. Three species new to Utah were identified including bitter cherry (''

Prunus emarginata ''Prunus emarginata'', the bitter cherry or Oregon cherry, is a species of '' Prunus'' native to western North America, from British Columbia south to Baja California, and east as far as western Wyoming and New Mexico. It is often found in re ...

'' (Dougl.) Walpers), common sandweed ('' Athysanus pusillus'' (Hook.) Greene), and Lemmon's onion ('' Allium lemmonii'' S. Wats.). Nineteen ferns and fern allies are present, 18 gymnosperms (conifers and Mormon teas), 150 species of monocots (including 86 grasses, 10 orchids, and 2 agaves, among others), with the remainder being dicots. The three largest families represented in the flora of Pine Valley Mountain include the

Asteraceae The family Asteraceae, alternatively Compositae, consists of over 32,000 known species of flowering plants in over 1,900 genera within the order Asterales. Commonly referred to as the aster, daisy, composite, or sunflower family, Compositae ...

with 160 species,

Poaceae Poaceae () or Gramineae () is a large and nearly ubiquitous family of monocotyledonous flowering plants commonly known as grasses. It includes the cereal grasses, bamboos and the grasses of natural grassland and species cultivated in lawns an ...

with 85 species, and

Fabaceae The Fabaceae or Leguminosae,International Code of Nomenc ...

with 63. The three largest genera and number of species collected are

Eriogonum ''Eriogonum'' is a genus of flowering plants in the family Polygonaceae. The genus is found in North America and is known as wild buckwheat. This is a highly species-rich genus, and indications are that active speciation is continuing. It incl ...

, 23,

Cryptantha ''Cryptantha'' is a genus of flowering plants in the borage family, Boraginaceae. They are known commonly as cat's eyes and popcorn flowers (the latter name is also used to refer to the closely related genus ''Plagiobothrys'',Hasenstab-Lehman, ...

, 20, and

Astragalus ''Astragalus'' is a large genus of over 3,000 species of herbs and small shrubs, belonging to the legume family Fabaceae and the subfamily Faboideae. It is the largest genus of plants in terms of described species. The genus is native to tempe ...

, 20. Some of the finds include: * Forked spleenwort ('' Asplenium septentrionale'' (L.) Hoffm.), a small grass-like fern found at a single high-elevation location north of Mill Flat. * Grape fern (''

Botrychium ''Botrychium'' is a genus of ferns, seedless vascular plants in the family Ophioglossaceae. ''Botrychium'' species are known as moonworts. They are small, with fleshy roots, and reproduce by spores shed into the air. One part of the leaf, the tr ...

'') found in the high meadows. * Young bristlecone pines (''

Pinus longaeva ''Pinus longaeva'' (commonly referred to as the Great Basin bristlecone pine, intermountain bristlecone pine, or western bristlecone pine) is a long-living species of bristlecone pine tree found in the higher mountains of California, Nevada, and ...

'' D.K. Bailey) are found along the very crest of the mountain especially near the summit of the Oak Grove trail and westward. * Sequoia tree (''

Sequoiadendron giganteum ''Sequoiadendron giganteum'' (giant sequoia; also known as giant redwood, Sierra redwood, Sierran redwood, California big tree, Wellingtonia or simply big treea nickname also used by John Muir) is the sole living species in the genus '' Sequoiad ...

'' (Lindl.) Buchholz). A single tree planted behind the Browse guard station is almost four feet in diameter. * Pistachios have escaped cultivation from old plantings near Leeds and Harrisburg. The rootstocks for those orchards were the Mount Atlas pistachio (''

Pistacia atlantica ''Pistacia atlantica'' is a species of pistachio tree known by the English common name Mt. Atlas mastic tree, Atlas pistachio, Atlantic pistacio, Atlantic terebinth, Cyprus turpentine tree, and Persian turpentine tree. ''P. atlantica'' has th ...

'' Desf.) while the upper portions of the trees were the edible pistachio ('' Pistacia vera'' L.). Some of the tops have died and trees have resprouted from the rootstocks and produced viable seeds. Birds have helped move them into the southern foothills of Pine Valley Mountain where they have become naturalized, often growing as bonsai trees out of cracks in rocks and cliffs. * Dollarjoint cactus (''

Opuntia chlorotica ''Opuntia chlorotica'' is a species of plant in the family Cactaceae. It is a species of prickly pear native to the southwestern United States and northern Mexico. Its common names include pancake prickly pear, flapjack prickly pear and dollarjo ...

'' Engelm. & Bigel.) scattered along the southern foothills. * A yellow-flowered population of Bridges penstemon (''

Penstemon rostriflorus ''Penstemon rostriflorus'' is a species of penstemon known by the common names beaked penstemon, Bridge penstemon, or Bridges' penstemon. It is native to the Southwestern United States and California, where it grows in many types of sagebrush, ...

'' Kellogg), along the south fork of Pinto Creek. * Three species of orchids in the genus ''

Corallorhiza ''Corallorhiza'', the coralroot, is a genus of flowering plants in the orchid family. Except for the circumboreal ''C. trifida'', the genus is restricted to North America (including Mexico, Central America and the West Indies). Most species are ...

''. * Pine Valley goldenbush (''

Ericameria ''Ericameria'' is a genus of North American shrubs in the family Asteraceae. ''Ericameria'' is known by the common names goldenbush, rabbitbrush, turpentine bush, and rabbitbush. Most are shrubs but one species ''( E. parishii)'' can reach tree ...

crispus'' (L.C. Anderson) G.L. Nesom), with its peculiar crinkled leaves, is only found in the Pine Valley Mountains, most commonly along the Whipple Trail in Hop Canyon. * Utah spikemoss ('' Selaginella utahensis'' Flowers) has an extremely limited distribution in southwestern Utah and one location in Nevada, but is locally common on Pine Valley Mountain wherever a shady spot and Navajo sandstone can be found together. All but one of Utah's conifers grow in the Pine Valley Mountains. Only the lodgepole pine (''

Pinus contorta ''Pinus contorta'', with the common names lodgepole pine and shore pine, and also known as twisted pine, and contorta pine, is a common tree in western North America. It is common near the ocean shore and in dry montane forests to the subalpine ...

'' Douglas) is missing.

Recreation

There are numerous opportunities for recreation in the mountains, including hiking, rock climbing, camping, wildlife watching, fishing, hunting, horseback riding, and boating on a reservoir.

Peaks

Gallery

File:Red Cliffs and Pine Valley Mountains.JPG, alt=A photo of the Red Cliffs with snow-capped Pine Valley Mountains in the background, Pine Valley Mountains File:Pine Valley Mountain from Lower Sand Cove at dusk 2009-06-10.jpg, alt=A photo of the Pine Valley Mountains from Lower Sand Cove, Pine Valley Mountain from Lower Sand Cove File:View from top of Hurrican Fault (La Verkin Hill) showing Pine Valley Mountain in distance with Vermillion Cliff... - NARA - 520420.jpg, alt=A photo of the Pine Valley Mountains from on top of the Hurricane Fault, Pine Valley Mountains File:Pine Valley Mountain and Red Cliffs, Utah.jpg, Sunrise on Pine Valley Mountain and Red Cliffs National Conservation Area, Utah File:Pine_Valley_Mountains_Contact_Between_Claron_and_Laccolith.jpg, Pine Valley Laccolith resting on top of the Claron Formation near the headwaters of Cottonwood Creek

References

External links

Dixie National Forest
fs.usda.gov {{authority control Dixie National Forest Mountain ranges of Washington County, Utah Mountain ranges of Utah Extinct volcanoes Miocene volcanoes