Entering the Beaverhead River Canyon

Entering the Beaverhead River Canyon. "the river entered the mountain…". , The point where the Beaverhead River entered the Blacktail Fault is marked by a dramatic change in the landscape. This fault uplifts the Blacktail Mountains over 9,000 feet. All of this topography (?) over the last six million years and the fault that caused it is still active! , The Beaverhead river Canyon formed (?) the Blacktail Mountains were uplifted, forcing the Beaverhead river to cut into the hard volcanic rock. The river is now still in those rocks and continues to cut the canyon as the mountains continue to be uplifted.
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"halted on the river under an immensely high perpendicular cliff of rock, cooked and eat haisty meal and departed… " Meriwether Lewis, August 10, 1805

, The Corps of Discovery passed through the "rattle snake clifs" quickly in 1805 distracted by the urgent need to find the Lemhi Shoshone people to procure horses and information about the trail ahead. , , The modern explorer, however, can take the time to appreciate the spectacular geology exposed by the relentless erosion of the Beaverhead River. , , At this point, the Beaverhead River, flowing north, crosses the Blacktail Fault and abruptly enters broad expanse of the Beaverhead Valley from the confines of a Canyon. The symbol :C" indicates the side of the fault that gone up, "D" indicates the side of that has gone down.