
The Laramie Mountains are shown highlighted on a map of the western United States
The 'Laramie Mountains' are a
range of moderately high peaks on the eastern edge of the
Rocky Mountains in the states of
Wyoming and
Colorado in the
United States. The range is the northernmost extension of the line of the ranges along the eastern side of the Rockies, an in particular of the higher peaks of the
Front Range directly to the south. North of the range, the gap between the Laramies and the
Bighorn Mountains provided the route for historical trails, such as the
Oregon Trail, the
Mormon Trail, and the
Pony Express.
The mountains extend northward from southeastern Wyoming between
Cheyenne and
Laramie, to
Casper. They are named after the
Laramie River, which cuts through the range from southwest to northeast and joins the
North Platte River east of the range in eastern Wyoming. The mountains in turn give their name to the
Laramide orogeny, the uplift of the of
North American Plate approximately 70 million years ago that created the present Rocky Mountains.
The mountains consist of a series of
Precambrian Sherman
granite monadnocks rising above a broad erosion surface ['1, 2'] that form extensive unwooded parks whose surfaces are generally at about ca. 7000 ft (2135 m) above sea level. The high peaks of the range, which are much lower than those commonly associated with the Rocky Mountains, rise abruptly above the surrounding
peneplain to altitudes between 8000 ft (2440m) and 9500 ft (2895m) above sea level, with the single exception of Laramie Peak which tops out at 10,274 ft (3130 m). The granitic soils were formed from the erosion of the surrounding monadnocks and have an effective depth of less than 12 inches (30 cm).
Three principal Life Zones are represented in the Laramies: Upper Sonoran, Transition and Canadian (''sensu'' Carpenter ['3']). Some early sources indicated that the Hudsonian Zone occurs on Laramie Peak but there is nothing distinctive about either the flora or fauna on the top of this peak, for it consists of nothing but a large granite outcrop. For further discussion of the Life Zones of this area, see Porter (1962) ['4'] as well as Cary ['5']. On the E and NE slopes of the Laramies the prairie/mountain transition is very gentle at the south end (between Cheyenne and Laramie) and much more abrupt and broken farther north ['6']. The elevation ranges from about ca. 4500' (1370 m) along the
North Platte River to 10,274' (3130 m) at the top of Laramie Peak. On the western slopes the total relief is much less, as the floors of the three
intermontane basins that border the Laramies on this side (Shirley, Hanna and Laramie basins) rarely drop below 7000'(2135m). An extensive high plain (7000-7900 ft/2135-2400 m) and semi-desert extends from the Laramie Mountains SW as far as the Shirley Mountains. The Laramie Basin separates the Laramie Mountains from the
Medicine Bow Mountains to the S and W, and its floor is above 2135 m except for a few depressions and
blowouts (''e.g''., Cooper Lake, 6980 ft, 2130m).
The Laramie Mountains are bisected by the
Laramie River, which cuts a canyon through the mountains roughly due west of
Wheatland, and then continues its generally eastward course to join the
North Platte River near the town of
Fort Laramie. The division marks the southern end of the continuous coniferous forest in the Laramies, and separates the range into two parts. The southern part is generally drier and much more open, with little or no forest except for the southern end at Pole Mountain and surrounding area, where the interesting granite outcrops at
Vedauwoo provide climbing practice and grand picnic scenery.
The range is prominently visible from
Interstate 25 between Casper and Cheyenne.
See also
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Geography of Colorado
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Mountain peaks of Colorado
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Mountain ranges of Colorado
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Rocky Mountains
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State of Colorado
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State of Wyoming
References
Further reading
★ Blackstone, D. L. 1971. Traveler's guide to the geology of Wyoming. Bulletin of the Geological Survey of Wyoming. 55:1-90.
★ Carpenter, J. R. 1956. An Ecological Glossary. Hafner, NY.
★ Cary, M., 1917. Life zone investigations in Wyoming. Bulletin USDA Biological Survey. 42: 1-95.
★ Dunbar, C. O. 1960. Historical Geology. J. Wiley & Sons, NY. 2nd Ed., fig. 308.
★ Hardesty, Richard L. and Groothuis, Dennis R. ''Butterflies of the Laramie Mountains, Wyoming (Lepidoptera: Rhopalocera.)'' The introduction provides additional information on the Laramie Mountains. A PDF version of this work may be downloaded at
Butterflies of the Laramie Mountains, Wyoming (Lepidoptera: Rhopalocera.).
★ Marshall, K. & Colbert, E. H. 1965. Stratigraphy and Life History. J. Wiley & Sons, NY.
★ Porter, C. L. 1962. A flora of Wyoming. Part I. Bulletin of the University of Wyoming Agricultural Experimental Station. 402.
External links
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Rocky Mountains @ Peakbagger
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Southern Rocky Mountains @ Peakbagger
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Laramie Mountains @ Peakbagger