Question: Colter Falls is part of the Great Falls of the Missouri River where the Lewis and Clark Expedition was known to discover a freshwater fish of what order?

Context paragraphs:
Rainbow Falls (Missouri River): Rainbow Falls (originally "Handsome Falls") is a waterfall on the Missouri River in Great Falls, Montana, just upstream from Crooked Falls and downstream from Colter Falls and Rainbow Dam.  It is 47 feet (14m) high and 1,320 feet (402.3m) wide.  The waterfall is part of the five Great Falls of the Missouri.  The river spills over a sheer ledge of sandstone in the Kootenai Formation, forming the falls.  The falls used to flow with a great deal of force year-round.  In 1914 the river shortly upstream was dammed for hydroelectric power by the Rainbow Dam, which forms a run-of-the-river reservoir.  As a result, the falls can almost totally dry up in the summer with only a few narrow strips of water trickling down its face.  A railroad bridge crosses the river directly above the falls.

Lewis and Clark Pass (Montana): Lewis and Clark Pass, el.  6424 ft is a mountain pass on the continental divide in Montana.  It lies at the head of the drainages of the west flowing Blackfoot River and the east flowing Dearborn River.  The pass is in the Helena National Forest in Lewis and Clark County.  The Continental Divide Trail traverses north and south through the pass.  At the time of the Lewis and Clark Expedition the pass was a much-used pathway where the native people living in what today is Montana crossed over the continental divide.  The pass was crossed by Meriwether Lewis on July 7, 1806, on the return leg of the Lewis and Clark Expedition with a party of nine men and his dog Seaman.  The pass was named for the expedition's two leaders–Lewis and William Clark.  Lewis and Clark Pass is the only roadless pass on the entire Lewis and Clark National Historic Trail.  It has gone from being one of the most used continental divide passes prior to the pioneer era to one of the least visited passes today.  It can be accessed by a 1.5 mi trail.  Visitors will encounter the pass much as Lewis did in 1806.  The furrows left by the countless dog and horse travois that crossed the pass are still visible (though fading) and this is one of the places along the expedition's route that visitors may still encounter a grizzly bear.  On a clear day, like Meriwether Lewis in 1806 one can see Square Butte in Cascade County, Montana, 40 mi to the northeast.

Colter's Hell: Colter's Hell is an area of fumaroles and hot springs on the Shoshone River near Cody in the U.S. state of Wyoming.  The thermal area covers about a square mile at the mouth of the Shoshone's canyon.  Its thermal activity has declined ever since its description by mountain man John Colter, who parted from the Lewis & Clark Expedition prior to its conclusion and passed through the region in the winter of 1807-1808.  Colter's account of the features on what was then called the Stinkingwater River has subsequently been confused with the much more extensive and powerful geysers in Yellowstone National Park, which Colter may not have actually visited.

Ryan Dam: Ryan Dam is a hydroelectric dam on the Missouri River, 10 mi downstream from the city of Great Falls in the U.S. state of Montana.  The dam is 1336 ft long and 61 ft high; its reservoir is 7 mi long and has a storage capacity of 5000 acre.ft .  It is a run-of-river dam.  The dam is built on the largest of the five Great Falls of the Missouri, and these specific falls are also called "Great Falls".  Since 1915, the six-unit powerhouse on the left side of the dam has occupied a significant portion of the 87 ft high waterfall.

Great Falls (Missouri River waterfall): Great Falls (also called Grand Falls or Big Falls) is a major waterfall located on the Missouri River in western Montana in the United States.  It is the lowermost and largest of the eponymous Great Falls of the Missouri, at 87 ft high and up to 900 ft wide at peak flow.  Although the falls used to flow powerfully year-round, most of the water is now diverted to the 60 megawatt hydroelectric plant of upstream Ryan Dam, reducing it to a trickle in the summer months.  Grand Falls was named by William Clark of the Lewis and Clark Expedition in 1805.

Great Falls (Catawba River): The Great Falls of the Catawba River mark the point at which the river encounters a series of rapids while coursing across the Piedmont Plateau on the border of Lancaster County, South Carolina, and Chester County, South Carolina, near the town of Great Falls.  Prior to the creation of the Fishing Creek Reservoir and other artificial lakes by Duke Power, the falls were a major landmark on the river.  The rapids could be heard from long distances away, while a major pre-Columbian trading path ran near the left bank.  Historically the Great Falls of the Catawba were approximately 4 miles long, with a total elevation drop of 121 feet.  (The word "falls" was an 18th-century appellation, when any river rapids and vertical waterfalls alike were both referred to as falls.)  The creation of the dams at Great Falls, South Carolina has resulted in the top 2 miles of it being completely dry (dewatered) except during times of very high flow.  The bottom portion of historical Great Falls is drowned by Cedar Creek dam, another hydroelectric project.  As of 2006, interest groups have formed in the Carolinas to restore the Great Falls by altering the dam and restoring flow to the dewatered stretch of Great Falls as part of a major restoration project of the Catawba River.  As of 2007, a new licensing arrangement has been agreed to by Duke Energy and several interested parties.

Great Falls Portage: The Great Falls Portage is the route taken by the Lewis and Clark Expedition in 1805 to portage around the Great Falls of the Missouri River during the outbound portion of the expedition.  The 18 mi portage took 31 days.  Two portions of the route, which have largely escaped development, are part of a National Historic Landmark District, designated in 1966 to commemorate this achievement.  In May 2008 the National Trust for Historic Preservation listed the site on their list of America's Most Endangered Places.

Westslope cutthroat trout: The westslope cutthroat trout ("Oncorhynchus clarki lewisi"), also known as the black-spotted trout, common cutthroat trout and red-throated trout is a subspecies of the cutthroat trout ("Oncorhynchus clarki") and is a freshwater fish in the salmon family (family Salmonidae) of order Salmoniformes.  The cutthroat is the Montana state fish.  This subspecies is a "species of concern" in its Montana and British Columbia ranges and is considered "threatened" in its native range in Alberta.

Ictiobus: Ictiobus, also known as buffalo fish or simply buffalo, is a genus of freshwater fish common in the United States, but also found in Canada, Mexico and Guatemala.  They are the largest North American suckers, reaching up to 1.23 m in length.  They are sometimes mistaken for carp because of the flat face and large, silver scales running along the body, though they lack the whisker-like mouth appendages common to carp.  Buffalo fish live in most types of freshwater bodies where panfish are found, such as ponds, creeks, rivers, and lakes.  "Ictiobus" was caught by the Lewis and Clark Expedition.

Colter Falls: Colter Falls, also Coulter Falls, (4.3m) waterfall, nearly 0.5 mi in width, part of the Great Falls of the Missouri, on the Missouri River in north-central Montana.  Downstream of Colter Falls lies Rainbow Falls, and upstream is Black Eagle Falls.  The Lewis and Clark Expedition was known to discover Westslope cutthroat trout at the base of the falls.  The falls is now flooded in the impoundment behind Rainbow Dam.  As Rainbow Dam's reservoir is a run-of-the-river reservoir, it rarely is emptied, so the falls is rarely seen even in extreme drought.  The falls was named by Paris Gibson, founder of the city of Great Falls, Montana, while they were not named by Lewis and Clark, who measured it at "6 feet 7 inches".

Supporting paragraphs: Colter Falls Westslope cutthroat trout
Answer: Salmoniformes