The Missouri River in Montana

August 03, 2005


Provided and copyright by: Rod Benson, Helena High School
Summary authors & editors: Rod Benson

Lewis and Clark were here, and so was Kevin Costner. This photo of the Missouri River, taken 30 miles (48 km) southwest of Great Falls, Montana on April 17, 2005, shows the area where the Corp of Discovery left the Great Plains and entered the mountains in mid-July of 1805. If the Lewis and Clark Expedition had passed through 75 million years earlier, they would have encountered an area of volcanic activity, measuring about 20 miles (32 km) in diameter, and including more than one volcanic cone. The journey from Great Falls to Montana's capitol city of Helena, on Interstate-15, passes through this ancient volcanic center. But, if you take this drive, don’t expect to see any volcanoes. Millions of years of erosion have worn them away, leaving a mountainous area of igneous rocks that geologists refer to as a “volcanic pile.”

This area is also where Paramount Pictures filmed a shootout scene for its 1987 movie titled "The Untouchables," starring Kevin Costner and Sean Connery. The bridge in the photo doubled as the Canadian border.

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