Columbia River Basalt Group
- Clearwater River (Idaho) (Wikipedia)
The Clearwater River is in the northwestern United States, in north central Idaho. Its length is 74.8 miles (120.4 km), it flows westward from the Bitterroot Mountains along the Idaho-Montana border, and joins the Snake River at Lewiston. In October 1805, the Lewis and Clark Expedition descended the Clearwater River in dugout canoes, putting in at “Canoe Camp,” five miles (8 km) downstream from Orofino; they reached the Columbia Bar and the Pacific Ocean about six weeks later.
Columbia River Basalt Group map shows main regions of basalt exposure in Washington, Oregon, Idaho and Nevada, USA. (usgs.gov)