ৰকি পৰ্বতমালা

অসমীয়া ৱিকিপিডিয়াৰ পৰা
ৰকি পৰ্বতমালা
the Rockies (en), les Rocheuses (fr),
Montañas Rocosas, Rocallosas (es)

Moraine Lake, and the Valley of the Ten Peaks, Banff National Park, Alberta, Canada
উচ্চতম শিখৰ
শৃংগ Mount Elbert (U.S.A.)
উচ্চতা 14,440 ফুট (4 মিটাৰ)
স্থানাংকসমূহ 39°07′03.90″N 106°26′43.29″W / 39.11775°N 106.4453583°W / 39.11775; -106.4453583
পৰিধি
দৈৰ্ঘ্য 3,000 মাইল (4 km)
ভূগোল
RockyMountainsLocatorMap.png
দেশসমূহ Canada and United States
States/Provinces
স্থানাংক প্ৰসাৰ 43°44′N 110°48′W / 43.74°N 110.8°W / 43.74; -110.8স্থানাংক: 43°44′N 110°48′W / 43.74°N 110.8°W / 43.74; -110.8
Parent range North American Cordillera
Geology
সময় Precambrian and Cretaceous
Type of rock Igneous, Sedimentary and Metamorphic

ৰকি পৰ্বতমালা (ইংৰাজী: Rocky Mountains) হৈছে উত্তৰ আমেৰিকাত অৱস্থিত পৰ্বতশ্ৰেণীসমূহৰ ভিতৰত অন্যতম এক পৰ্বতমালা৷ ই ব্ৰিটিছ কলম্বিয়া,পশ্চিম কানাডাৰ পৰা নিউ মেক্সিক', দক্ষিণ-পশ্চিম আমেৰিকা যুক্তৰাষ্ট্ৰ লৈকে ৩০০০ মাইল পৰ্যন্ত বিস্তৃত হৈ আছে৷ ৰকি পৰ্বতমালাৰ পোনপ্ৰথমে সৃষ্টি হৈছিল ৫৫-৮০মিলিয়ন বছৰ পূ্ৰ্বে লাৰামাইড অ'ৰ'জেনি (Laramide Orogeny) ৰ কালত৷ এই সময়ছোৱাত উত্তৰ আমেৰিকা টেক্ট'নিক প্লেট ( North American plate)ৰ তলত থকা কেইবাখনো টেক্ট'নিক প্লেটৰ স্থানান্তৰ ঘটে৷ ইয়াৰ ফলত পশ্চিমৰ উত্তৰ আমেৰিকাত এক পৰ্বতমালাৰ সৃষ্টি হয়৷ পৰৱৰ্ত্তী কালত অন্যান্য টেক্ট'নিক পৰিৱৰ্ত্তন আৰু গ্লেচিয়াৰ সমূহৰ স্খলনৰ ফলত ৰকি পৰ্বতমালাৰ বিভিন্ন শৃংগ আৰু উপত্যকাৰ গঢ় লয়৷ অন্তিমটো হিমযুগ (ice age)ৰ পৰা ৰকি পৰ্বতমালালৈ মানুহৰ আগমণ ঘটে আৰু স্থায়ীভাবে বসবাস কৰিবলৈ লয়৷ ছাৰ আলেকজেণ্ডাৰ মেকেঞ্জি ( Alexander Mackenzie) ৰ দৰে ইউৰোপিয়ান সকলৰ পিছত বিভিন্ন আমেৰিকান অভিযান যেনে লিউৱিছ আৰু ক্লাৰ্ক অভিযান ( Lewis and Clark expedition) ৰ জৰিয়তে এই পৰ্বতমালাত অৱৰোহণ কৰে৷

বৰ্তমান এই পৰ্বতমালাৰ সৰহ অংশই সমজুৱা উদ্যান বা সংৰক্ষিত বনাঞ্চলেৰে আবৃত৷ সেইবাবে ই পৰ্যটকৰ বাবে বিশেষ আকৰ্ষণতো পৰিণত হৈছে৷

ভৌগোলিক বিৱৰণ[সম্পাদনা কৰক]

ভৌগোলিকভাবে ৰকি পৰ্বতমালা দক্ষিণে বৃটিছ কলম্বিয়াৰ লিয়াৰ্ড নদী (Liard river) ৰ পৰা নিউ মেক্সিক'ৰ ৰিঅ' গ্ৰেণ্ড (Rio Grande) পৰ্যন্ত বিস্তৃত হৈ আছে৷ এই দুই নদীৰ সিপাৰে অন্য কিছু পৰ্বত যেনে, য়ুকুন (Yukon)ৰ শ্বেলৱিন ৰেঞ্জ (Selwyn Range), আলাস্কাৰ ব্ৰুকছ ৰেঞ্জ (Brooks Range) আৰু মেক্সিক'ৰ শ্বিয়েৰা মাদ্ৰে (Sierra Madre) আদি অৱস্থিত যদিও এই পৰ্বতসমূহ ৰকি পৰ্বতমালাৰ অংশ নহয়৷ অৱশ্যে আমেৰিকা যুক্তৰাষ্টহৱত প্ৰচলিত সীমা অনুসৰি কুটেনাই নদী (Kootenai river) ৰ দক্ষিণে থকা পৰ্বতসমূহ ৰকি পৰ্বতমালাৰ অন্তৰ্ভুক্তবুলি ধৰা হয় কিন্তু উত্তৰে থকা পৰ্বতশ্ৰেণীক পৃথক বুলি গণ্য কৰা হয়[1]৷ ৰকি পৰ্বতমালাৰ পৰ্বতসমূহ প্ৰায় ৭০-৩০০ মাইল (১১০-৪৮০ কিলোমিটাৰ) পৰ্যন্ত বহল বুলি জনা যায়৷

The eastern edge of the Rocky Mountains near Denver

ৰকি পৰ্বতমালাৰ উত্তৰ অংশৰ কেন্দ্ৰীয় উত্তৰ আমেৰিকাত উচ্চতা বৃদ্ধি পায়৷ এই অংশতে কলেৰেডোৰ ফ্ৰণ্ট ৰেঞ্জ (Front range) , Wyoming ৰ Wind River range, Big Horn Mountains , Absaroka-Beartooth range আৰু মন্টানাৰ ৰকি মাউণ্টেইন ফ্ৰণ্ট (Rocky Mountain Front ) অৱস্থিত ৷ কানাডাত আকৌ ভূগোলবিদ সকলে ৰকি পৰ্বতমালাৰ তিনিটা সমষ্টি চিনাক্ত কৰিছে: Continental Range, Hart Ranges আৰু Muskwa Range৷ এই হাৰ্ট ৰেঞ্জ আৰু মুশ্বকোৱা ৰেঞ্জে একেলগে উত্তৰ ৰকি পৰ্বতমালা (Northern Rockies) সৃষ্টি কৰিছে৷

The Tetons are a rugged subrange in Wyoming

ৰকি পৰ্বতমালাৰ পশ্চিম অংশত চল্ট লেক নগৰৰ কাষৰীয়া Wasatch range আৰু ইডাহ'-মন্টানা সীমা (Idaho-Montana) ত থকা Bitterroots আদি পৰ্বত অৱস্থিত৷ The Great Basin and Columbia River Plateau separate these sub-ranges from distinct ranges further to the west, most prominent among which are the Sierra Nevada, Cascade Range and Coast Mountains. The Rockies do not extend into the Yukon or Alaska, or into central British Columbia, where the Rocky Mountain System (but not the Rocky Mountains) includes the Columbia Mountains, the southward extension of which is considered part of the Rockies in the United States. The Rocky Mountain System within the United States is a United States physiographic region; the Rocky Mountain System is known in Canada as the Eastern System.

The Rocky Mountains are notable for containing the highest peaks in central North America. The range's highest peak is Mount Elbert located in Colorado at Lua error in Module:Convert at line 696: attempt to index local 'utable' (a nil value). above sea level. Mount Robson in British Columbia, at Lua error in Module:Convert at line 696: attempt to index local 'utable' (a nil value)., is the highest peak in the Canadian Rockies.

Human population is not very dense in the Rocky Mountains, with an average of four people per square kilometer (10 per square mile) and few cities with over 50,000 people. However, the human population grew rapidly in the Rocky Mountain states between 1950 and 1990. The 40-year statewide increases in population range from 35% in Montana to about 150% in Utah and Colorado. The populations of several mountain towns and communities have doubled in the last 40 years. Jackson Hole, Wyoming, increased 260%, from 1,244 to 4,472 residents, in 40 years.[2]

ভূবিজ্ঞান[সম্পাদনা কৰক]

The rocks in the Rocky Mountains were formed before the mountains were raised by tectonic forces. The oldest rock is Precambrian metamorphic rock that forms the core of the North American continent. There is also Precambrian sedimentary argillite, dating back to 1.7 billion years ago. During the Paleozoic, western North America lay underneath a shallow sea, which deposited many kilometers of limestone and dolomite.[3]

Glaciers, such as Jackson Glacier in Glacier National Park, Montana, as shown here, have dramatically shaped the Rocky Mountains.

জলবায়ু তথা প্ৰকৃতিক বিৱৰণ[সম্পাদনা কৰক]

There are a wide range of environmental factors in the Rocky Mountains. The Rockies range in latitude between the Liard River in British Columbia (at 59° N) and the Rio Grande in New Mexico (at 35° N). Prairie occurs at or below Lua error in Module:Convert at line 696: attempt to index local 'utable' (a nil value)., while the highest peak in the range is Mount Elbert at Lua error in Module:Convert at line 696: attempt to index local 'utable' (a nil value).. Precipitation ranges from Lua error in Module:Convert at line 696: attempt to index local 'utable' (a nil value). per year in the southern valleys[4] to Lua error in Module:Convert at line 696: attempt to index local 'utable' (a nil value). per year locally in the northern peaks.[5] Average January temperatures can range from Lua error in Module:Convert at line 696: attempt to index local 'utable' (a nil value). in Prince George, British Columbia, to Lua error in Module:Convert at line 696: attempt to index local 'utable' (a nil value). in Trinidad, Colorado.[6] Therefore, there is not a single monolithic ecosystem for the entire Rocky Mountain Range.

Tundra in the Rocky Mountains of Colorado

Instead, ecologists divide the Rocky Mountain into a number of biotic zones. Each zone is defined by whether it can support trees, and the presence of one or more indicator species. Two zones that do not support trees are the Plains and the Alpine tundra. The Great Plains lie to the east of the Rockies, and is characterized by prairie grasses (below roughly Lua error in Module:Convert at line 696: attempt to index local 'utable' (a nil value).). Alpine tundra occurs in regions above the treeline for the Rocky Mountains, which varies from Lua error in Module:Convert at line 696: attempt to index local 'utable' (a nil value). in New Mexico to Lua error in Module:Convert at line 696: attempt to index local 'utable' (a nil value). at the northern end of the Rocky Mountains (near the Yukon).[6]

The USGS defines ten forested zones in the Rocky Mountains.[2] Zones in more southern, warmer, or drier areas are defined by the presence of pinyon pines/junipers, ponderosa pines, or oaks mixed with pines. In more northern, colder, or wetter areas, zones are defined by Douglas-firs, Cascadian species (such as western hemlock), lodgepole pines/quaking aspens, or firs mixed with spruce. Near treeline, zones can consist of white pines (such as whitebark pine or bristlecone pine); or a mixture of white pine, fir, and spruce that appear as shrub-like krummholz. Finally, rivers and canyons can create a unique forest zone in more arid parts of the mountain range.[2]

Bighorn sheep (such as this lamb in Alberta) have declined dramatically since European-American settlement of the Rocky Mountains.

The Rocky Mountains are an important habitat for a great deal of well-known wildlife, such as elk, moose, mule and white-tailed deer, pronghorns, mountain goats, bighorn sheep, badgers, black bears, grizzly bears, coyotes, lynxes, and wolverines.[2] For example, North America's largest herds of moose is in the Alberta-British Columbia foothills forests.

The status of most species in the Rocky Mountains is unknown, due to incomplete information. European-American settlement of the mountains has adversely impacted native species. Examples of some species that have declined include western toads, greenback cutthroat trouts, white sturgeons, white-tailed ptarmigans, trumpeter swans, and bighorn sheep. In the United States portion of the mountain range, apex predators such as grizzly bears and gray wolves had been extirpated from their original ranges, but have partially recovered due to conservation measures and reintroduction. Other recovering species include the bald eagle and the peregrine falcon.[2]

ইতিহাস[সম্পাদনা কৰক]

Indigenous People[সম্পাদনা কৰক]

Since the last great ice age, the Rocky Mountains were home first to indigenous peoples including the Apache, Arapaho, Bannock, Blackfoot, Cheyenne, Crow Nation, Flathead, Shoshone, Sioux, Ute, Kutenai (Ktunaxa in Canada), Sekani, Dunne-za, and others.[2] Paleo-Indians hunted the now-extinct mammoth and ancient bison (an animal 20% larger than modern bison) in the foothills and valleys of the mountains. Like the modern tribes that followed them, Paleo-Indians probably migrated to the plains in fall and winter for bison and to the mountains in spring and summer for fish, deer, elk, roots, and berries. In Colorado, along the crest of the Continental Divide, rock walls that Native Americans built for driving game date back 5,400–5,800 years.[2] A growing body of scientific evidence indicates that indigenous people had significant effects on mammal populations by hunting and on vegetation patterns through deliberate burning.[2]

European exploration[সম্পাদনা কৰক]

Recent human history of the Rocky Mountains is one of more rapid change.[2] The Spanish explorer Francisco Vásquez de Coronado—with a group of soldiers, missionaries, and African slaves—marched into the Rocky Mountain region from the south in 1540.[7] The introduction of the horse, metal tools, rifles, new diseases, and different cultures profoundly changed the Native American cultures. Native American populations were extirpated from most of their historical ranges by disease, warfare, habitat loss (eradication of the bison), and continued assaults on their culture.[2]

In 1739, French fur traders Pierre and Paul Mallet, while journeying through the Great Plains, discovered a range of mountains at the headwaters of the Platte River, which local American Indian tribes called the "Rockies", becoming the first Europeans to report on this uncharted mountain range.[8]

Sir Alexander MacKenzie in 1800

Sir Alexander MacKenzie (1764–March 11, 1820) became the first European to cross the Rocky Mountains in 1793.[9] He found the upper reaches of the Fraser River and reached the Pacific coast of what is now Canada on July 20 of that year, completing the first recorded transcontinental crossing of North America north of Mexico.[10] He arrived at Bella Coola, British Columbia, where he first reached saltwater at South Bentinck Arm, an inlet of the Pacific Ocean.

The Lewis and Clark Expedition (1804–1806) was the first scientific reconnaissance of the Rocky Mountains.[11] Specimens were collected for contemporary botanists, zoologists, and geologists.[2] The expedition was said to have paved the way to (and through) the Rocky Mountains for European-Americans from the East, although Lewis and Clark met at least 11 European-American mountain men during their travels.[2]

Mountain men, primarily French, Spanish, and British, roamed the Rocky Mountains from 1720 to 1800 seeking mineral deposits and furs. The fur-trading North West Company established Rocky Mountain House as a trading post in what is now the Rocky Mountain Foothills of present-day Alberta in 1799, and their business rivals the Hudson's Bay Company established Acton House nearby.[12] These posts served as bases for most European activity in the Canadian Rockies in the early 19th century. Among the most notable are the expeditions of David Thompson (explorer), who followed the Columbia River to the Pacific Ocean.[13] On his 1811 expedition, he camped at the junction of the Columbia River and the Snake River and erected a pole and notice claiming the area for the United Kingdom and stating the intention of the North West Company to build a fort at the site.[14]

By the Anglo-American Convention of 1818, which established the 49th parallel north as the international boundary west from Lake of the Woods to the "Stony Mountains";[15] the UK and the USA agreed to what has since been described as "joint occupancy" of lands further west to the Pacific Ocean. Resolution of the territorial and treaty issues, the Oregon dispute, was deferred until a later time.

In 1819, Spain ceded their rights north of the 42nd Parallel to the United States, though these rights did not include possession and also included obligations to Britain and Russia concerning their claims in the same region.

After 1802, American fur traders and explorers ushered in the first widespread Caucasian presence in the Rockies south of the 49th parallel. The more famous of these include Americans William Henry Ashley, Jim Bridger, Kit Carson, John Colter, Thomas Fitzpatrick, Andrew Henry, and Jedediah Smith. On July 24, 1832, Benjamin Bonneville led the first wagon train across the Rocky Mountains by using South Pass in the present State of Wyoming.[2] Similarly, in the wake of Mackenzie's 1793 expedition, fur trading posts were established west of the Northern Rockies in a region of the northern Interior Plateau of British Columbia which came to be known as New Caledonia, beginning with Fort McLeod (today's community of McLeod Lake) and Fort Fraser, but ultimately focused on Stuart Lake Post (today's Fort St. James).

Negotiations between the United Kingdom and the United States over the next few decades failed to settle upon a compromise boundary and the Oregon Dispute became important in geopolitical diplomacy between the British Empire and the new American Republic. In 1841 James Sinclair, Chief Factor of the Hudson's Bay Company, guided some 200 settlers from the Red River Colony west to bolster settlement around Fort Vancouver in an attempt to retain the Columbia District for Britain. The party crossed the Rockies into the Columbia Valley, a region of the Rocky Mountain Trench near present-day Radium Hot Springs, British Columbia, then traveled south. Despite such efforts, in 1846, Britain ceded all claim to Columbia District lands south of the 49th parallel to the United States; as resolution to the Oregon boundary dispute by the Oregon Treaty.[16]

Cherokee Trail near Fort Collins, Colorado, from a sketch taken 7 June 1859.

Thousands passed through the Rocky Mountains on the Oregon Trail beginning in the 1840s.[17] The Mormons began to settle near the Great Salt Lake in 1847.[18] From 1859 to 1864, gold was discovered in Colorado, Idaho, Montana, and British Columbia, sparking several gold rushes bringing thousands of prospectors and miners to explore every mountain and canyon and to create the Rocky Mountains' first major industry. The Idaho gold rush alone produced more gold than the California and Alaska gold rushes combined and was important in the financing of the Union Army during the American Civil War. The transcontinental railroad was completed in 1869,[19] and Yellowstone National Park was established as the world's first national park in 1872.[20] Meanwhile, a transcontinental railroad in Canada was originally promised in 1871. Though political complications pushed its completion to 1885, the Canadian Pacific Railway eventually followed the Kicking Horse and Rogers Passes to the Pacific Ocean.[21] Canadian railway officials also convinced Parliament to set aside vast areas of the Canadian Rockies as Jasper, Banff, Yoho, and Waterton Lakes National Parks, laying the foundation for a tourism industry which thrives to this day. Glacier National Park (MT) was established with a similar relationship to tourism promotions by the Great Northern Railway.[22] While settlers filled the valleys and mining towns, conservation and preservation ethics began to take hold. U.S. President Harrison established several forest reserves in the Rocky Mountains in 1891–1892. In 1905, U.S. President Theodore Roosevelt extended the Medicine Bow Forest Reserve to include the area now managed as Rocky Mountain National Park.[2] Economic development began to center on mining, forestry, agriculture, and recreation, as well as on the service industries that support them.[2] Tents and camps became ranches and farms, forts and train stations became towns, and some towns became cities.[2]

অৰ্থনীতি[সম্পাদনা কৰক]

Industry and development[সম্পাদনা কৰক]

Economic resources of the Rocky Mountains are varied and abundant. Minerals found in the Rocky Mountains include significant deposits of copper, gold, lead, molybdenum, silver, tungsten, and zinc. The Wyoming Basin and several smaller areas contain significant reserves of coal, natural gas, oil shale, and petroleum. For example, the Climax mine, located near Leadville, Colorado, was the largest producer of molybdenum in the world. Molybdenum is used in heat-resistant steel in such things as cars and planes. The Climax mine employed over 3,000 workers. The Coeur d'Alene mine of northern Idaho produces silver, lead, and zinc. Canada's largest coal mines are near Fernie, British Columbia and Sparwood, British Columbia; additional coal mines exist near Hinton, Alberta,[2] and in the Northern Rockies surrounding Tumbler Ridge, British Columbia.

A drilling rig drills for natural gas just west of the Wind River Range in the Wyoming Rockies

The Rocky Mountains contain several sedimentary basins that are rich in coalbed methane. Coalbed methane is natural gas that arises from coal, either through bacterial action, or through exposure to high temperature. Coalbed methane supplies 7 percent of the natural gas used in the United States. The largest coalbed methane sources in the Rocky Mountains are in the San Juan Basin in New Mexico and Colorado and the Powder River Basin in Wyoming. These two basins are estimated to contain 38 trillion cubic feet of gas. Coalbed methane can be recovered by dewatering the coal bed, and separating the gas from the water; or injecting water to fracture the coal to release the gas (so-called hydraulic fracturing).[23]

Agriculture and forestry are major industries. Agriculture includes dryland and irrigated farming and livestock grazing. Livestock are frequently moved between high-elevation summer pastures and low-elevation winter pastures,[2] a practice known as transhumance.

পৰ্যটন[সম্পাদনা কৰক]

Castle Geyser in Yellowstone National Park
Going to the Sun Mountain in Glacier National Park

See also: List of U.S. Rocky Mountain ski resorts, List of Alberta ski resorts, List of B.C. ski resorts

Every year the scenic areas and recreational opportunities of the Rocky Mountains draw millions of tourists.[2] The main language of the Rocky Mountains is English. But there are also linguistic pockets of Spanish and indigenous languages. French is another official language in Canada's national parks.

People from all over the world visit the sites to hike, camp, or engage in mountain sports.[2] In the summer season, examples of tourist attractions are:

In the United States:

In Canada, the mountain range contains these national parks:

Glacier National Park in Montana and Waterton Lakes National Park in Alberta border each other and collectively are known as Waterton-Glacier International Peace Park. (See also International Peace Park.)

In the winter, skiing is the main attraction. A list of the major ski resorts can be found at List of U.S. Rocky Mountain ski resorts.

The adjacent Columbia Mountains in British Columbia contain major resorts such as Panorama and Kicking Horse, as well as Mount Revelstoke National Park and Glacier National Park.

There are numerous provincial parks in the British Columbia Rockies, the largest and most notable being Mount Assiniboine Provincial Park, Mount Robson Provincial Park, Northern Rocky Mountains Provincial Park, Kwadacha Wilderness Provincial Park, Stone Mountain Provincial Park and Muncho Lake Provincial Park.

লগতে চাওক[সম্পাদনা কৰক]

Needles of larches in Alberta turn yellow in autumn.

তথ্যসুত্ৰ[সম্পাদনা কৰক]

  1. Cannings, Richard (2007). The Rockies: A Natural History. Greystone/David Suzuki Foundation. পৃষ্ঠা. 5. ISBN 9781553652854. http://books.google.com/?id=ig4OMokvt-0C&pg=PA5&dq=%22Rocky+Mountain+Trench%22+and+%22Columbia+Mountains%22#v=onepage&q=%22Rocky%20Mountain%20Trench%22%20and%20%22Columbia%20Mountains%22&f=false. 
  2. 2.00 2.01 2.02 2.03 2.04 2.05 2.06 2.07 2.08 2.09 2.10 2.11 2.12 2.13 2.14 2.15 2.16 2.17 2.18 2.19 উদ্ধৃতি ত্ৰুটি: অবৈধ <ref> টেগ; USGS নামৰ refৰ বাবে কোনো পাঠ্য প্ৰদান কৰা হোৱা নাই
  3. Gadd, Ben (2008). "Geology of the Rocky Mountains and Columbias". Archived from the original on 2012-04-20. http://www.webcitation.org/673vl3jwm। আহৰণ কৰা হৈছে: 2010-01-01. 
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  5. "Southern Rocky Mountains". Forest Encyclopedia Network. http://wayback.archive.org/web/20110721043620/http://www.forestencyclopedia.net/p/p378। আহৰণ কৰা হৈছে: 2010-08-22. 
  6. 6.0 6.1 Sheridan, Scott. "US & Canada: Rocky Mountains (Chapter 14)". Geography of the United States and Canada course notes. Kent State University. Archived from the original on 2006-09-01. http://web.archive.org/web/20060901204453/http://sheridan.geog.kent.edu/geog17064/17064-14.pdf. 
  7. "Events in the West (1528-1536)". 2001. http://www.pbs.org/weta/thewest/events/1500_1650.htm। আহৰণ কৰা হৈছে: 15 April 2012. 
  8. PBS—THE WEST—Events from 1650 to 1800
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  10. "First Crossing of North America National Historic Site of Canada". http://www.historicplaces.ca/en/rep-reg/place-lieu.aspx?id=14662&pid=0। আহৰণ কৰা হৈছে: 15 April 2012. 
  11. "Lewis and Clark Expedition: Scientific Encounters". http://www.nps.gov/nr/travel/lewisandclark/encounters.htm। আহৰণ কৰা হৈছে: 15 April 2012. 
  12. "Rocky Mountain House National Historic Site of Canada". 28 Feb 2012. http://www.pc.gc.ca/lhn-nhs/ab/rockymountain/index.aspx। আহৰণ কৰা হৈছে: 15 April 2012. 
  13. "Guide to the David Thompson Papers 1806-1845". 2006. http://nwda-db.wsulibs.wsu.edu/findaid/ark:/80444/xv07195। আহৰণ কৰা হৈছে: 15 April 2012. 
  14. Oldham, kit (23 Jan 2003). "David Thompson plants the British flag at the confluence of the Columbia and Snake rivers on July 9, 1811.". http://www.historylink.org/index.cfm?DisplayPage=output.cfm&file_id=5096। আহৰণ কৰা হৈছে: 15 April 2012. 
  15. "Treaties in Force". 1 Nov 2007. http://www.state.gov/documents/organization/83046.pdf। আহৰণ কৰা হৈছে: 15 April 2012. 
  16. "Historical Context and American Policy". http://content.lib.washington.edu/curriculumpackets/treaties/assimilation2.html। আহৰণ কৰা হৈছে: 15 April 2012. 
  17. "Oregon Trail Interpretive Center". http://www.blm.gov/or/oregontrail/history-basics.php। আহৰণ কৰা হৈছে: 15 April 2012. 
  18. "The Mormon Trail". http://cdrh.unl.edu/diggingin/trailsummaries/di.sum.0006.html। আহৰণ কৰা হৈছে: 15 April 2012. 
  19. "The Transcontinental Railroad". 2012. http://www.calisphere.universityofcalifornia.edu/themed_collections/subtopic2b.html। আহৰণ কৰা হৈছে: 15 April 2012. 
  20. "Yellowstone National Park". 4 April 2012. http://www.nps.gov/yell/index.htm। আহৰণ কৰা হৈছে: 15 April 2012. 
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  22. "Glaciers and Glacier National Park". 2011. https://www.e-education.psu.edu/geosc10/l7_p3.html। আহৰণ কৰা হৈছে: 15 April 2012. 
  23. "Coal-Bed Gas Resources of the Rocky Mountain Region". USGS. USGS fact sheet 158-02. http://pubs.usgs.gov/fs/fs-158-02/fs-158-02.html. 

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