Split Rock, also known as Twin Peaks, is a mountain in the Granite Mountains of central

Wyoming Wyoming ( ) is a landlocked U.S. state, state in the Mountain states, Mountain West subregion of the Western United States, Western United States. It borders Montana to the north and northwest, South Dakota and Nebraska to the east, Idaho t ...

. The peak has an elevation of , and is located about north of the Muddy Gap junction between Casper and Rawlins. The mountain is distinctive for a deep V-shaped cleft dividing its summit. The mountain was a prominent landmark on the

Oregon Trail The Oregon Trail was a east–west, large-wheeled wagon route and Westward Expansion Trails, emigrant trail in North America that connected the Missouri River to valleys in Oregon Territory. The eastern part of the Oregon Trail crossed what ...

and other early settlement routes in the region, which crossed a low rise at the eastern end of the range between Casper and the

North Platte River The North Platte River is a major tributary of the Platte River and is approximately long, counting its many curves.U.S. Geological Survey. National Hydrography Dataset high-resolution flowline dataThe National Map accessed March 21, 2011 I ...

valley and the Sweetwater River. The mountain summit was listed on the

National Register of Historic Places The National Register of Historic Places (NRHP) is the Federal government of the United States, United States federal government's official United States National Register of Historic Places listings, list of sites, buildings, structures, Hist ...

in 1976 for its historic significance.

Geology

Fifty million years ago the Sweetwater River Valley and the Granite Range began to form. The range was created as a segment of the

Rocky Mountains The Rocky Mountains, also known as the Rockies, are a major mountain range and the largest mountain system in North America. The Rocky Mountains stretch in great-circle distance, straight-line distance from the northernmost part of Western Can ...

. Then, fifteen million years ago the area dropped downward creating a bowl. The erosion of the surrounding highlands, accumulated to . As the area continued downward, ‘Moonstone Lake’ formed about ten million years ago. It as large, shallow, and briny, adding an additional of sediments, with some

uranium Uranium is a chemical element; it has chemical symbol, symbol U and atomic number 92. It is a silvery-grey metal in the actinide series of the periodic table. A uranium atom has 92 protons and 92 electrons, of which 6 are valence electrons. Ura ...

concentrations. The erosion, stripped the surrounding high points, exposing the Granite Range.Split Rock, Twin Peaks; National Register of Historic Places Inventory—Nomination Form; Mark Junge, historian, Wyoming Recreation Commission; United States Department of the Interior National Park Service; December 20, 1976 The Continental Divide follows the southern rim of the basin, encompassing the Wind River and Sweetwater Valleys, following the crest of the Wind River Range, with the eastward extension including (east to west) the Ferris Mountains,

Green Mountains The Green Mountains are a mountain range in the U.S. state of Vermont and are a subrange of the Appalachian Mountains. The range runs primarily south to north and extends approximately from the border with Massachusetts to the border with Que ...

, Crooks Mountain and the Antelope Hills. There are a few breaks in this range of mountains, i.e., Muddy Gap, Crooks Gap and the broad slope called South Pass. This extended valley is a natural ramp built from the sands of ancient Moonstone Lake. The Sweetwater serpentine s through the eastern basin as a clear mountain stream. It has easy slopes, fresh water, and abundant grass. By pack train, wagon or handcart traveled the nineteenth century emigrant, seeking as direct a route as possible through the Great Plains and Rocky Mountains. The Sweetwater segment begins near the Alcova Reservoir, leaving the valley of the

. After it exits through South Pass.

History

The Sweetwater River Valley is a break in the Rocky Mountain chain. It thus provides a major, east-west overland route through the Rocky Mountains. This route was used by

fur trappers The fur trade is a worldwide industry dealing in the acquisition and sale of animal fur. Since the establishment of a world fur market in the early modern period, furs of boreal, polar and cold temperate mammalian animals have been the most ...

, goldseekers, homeseekers, merchants and troopers. They rode horseback, in wagons, walked, or pulled and pushed handcarts from 1812 to 1912. Beginning with the Astorians under Robert Stuart seeking a route to the mouth of the

Columbia River The Columbia River (Upper Chinook language, Upper Chinook: ' or '; Sahaptin language, Sahaptin: ''Nch’i-Wàna'' or ''Nchi wana''; Sinixt dialect'' '') is the largest river in the Pacific Northwest region of North America. The river headwater ...

for furs. Through the

California Trail The California Trail was an emigrant trail of about across the western half of the North American continent from Missouri River towns to what is now the state of California. After it was established, the first half of the California Trail f ...

, the

, and the

Mormon Pioneer Trail The Mormon Trail is the route from Illinois to Utah on which Mormon pioneers (members of the Church of Jesus Christ of Latter-day Saints) traveled from 1846 to 1869. Today, the Mormon Trail is a part of the United States National Trails Syste ...

. Before 1812, portions of the trail were used by High Plains American Indians following migratory herds of

buffalo Buffalo most commonly refers to: * True buffalo or Bubalina, a subtribe of wild cattle, including most "Old World" buffalo, such as water buffalo * Bison, a genus of wild cattle, including the American buffalo * Buffalo, New York, a city in the n ...

or other game animals. By 1912 the railroads, then the

automobile A car, or an automobile, is a motor vehicle with wheels. Most definitions of cars state that they run primarily on roads, Car seat, seat one to eight people, have four wheels, and mainly transport private transport#Personal transport, peopl ...

and

airplane An airplane (American English), or aeroplane (Commonwealth English), informally plane, is a fixed-wing aircraft that is propelled forward by thrust from a jet engine, Propeller (aircraft), propeller, or rocket engine. Airplanes come in a vari ...

replaced the wagon trail.

References

{{Authority control Natural features on the National Register of Historic Places in Wyoming Mountains of Natrona County, Wyoming

Geology

History

See also

References