Exit Tunnel
A park visitor stands in the exit tunnel of The Lewis and Clark Caverns in Montana. This 538 foot tunnel was the most significant accomplishment of the Civilian Conservation Corps during their time at Lewis and Clark Caverns during their 1935-41 stay. The exit tunnel allows visitors to exit the cavern without having to turn around and retrace the tedious route back through the cave. The cave entrance and other historic roads and facilities are part of the Lewis and Clark Caverns Historic District listed on the National Register of Historic Places in 2018.
Geologically the Lewis and Clark Caverns are located in a group of carbonate rocks called the Madison Limestone which is Mississippian in age. The caves formed at the base of one of the units of the Madison, the Mississippian Mission Canyon Limestone. There groundwater flow was perched above a less-soluble unit of the Madison called the Lodgepole Limestone. Because the beds were inclined, the CCC dug the exit tunnel in the Lodgepole Limestone straight back until it reached the caves in the Mission Canyon.
Exit Tunnel
A park visitor stands in the exit tunnel of The Lewis and Clark Caverns in Montana. This 538 foot tunnel was the most significant accomplishment of the Civilian Conservation Corps during their time at Lewis and Clark Caverns during their 1935-41 stay. The exit tunnel allows visitors to exit the cavern without having to turn around and retrace the tedious route back through the cave. The cave entrance and other historic roads and facilities are part of the Lewis and Clark Caverns Historic District listed on the National Register of Historic Places in 2018.
Geologically the Lewis and Clark Caverns are located in a group of carbonate rocks called the Madison Limestone which is Mississippian in age. The caves formed at the base of one of the units of the Madison, the Mississippian Mission Canyon Limestone. There groundwater flow was perched above a less-soluble unit of the Madison called the Lodgepole Limestone. Because the beds were inclined, the CCC dug the exit tunnel in the Lodgepole Limestone straight back until it reached the caves in the Mission Canyon.