Lewis and Clark Caverns

Lewis and Clark Caverns State Park is located in southeastern Jefferson County, Montana. The primary feature of the park is its namesake cavern.

The cavern was discovered in 1892 by Dan A. Morrison. The site was first established as "Lewis and Clark Cavern National Monument" on May 11, 1908, but was not fully surveyed and declared until May 16, 1911 by President Taft as 160 acres (0.65 km²). The limestone cave is named after the explorers Meriwether Lewis and William Clark since the cavern overlooks over 50 miles (80 km) of the trail from the Lewis and Clark Expedition along the Jefferson River, although Lewis and Clark never saw the cavern. It is located approximately 45 miles (72 km) west of Bozeman, Montana, and 60 miles (97 km) northwest from the northwest corner of Yellowstone National Park.

The caverns are also notable in that much of the work done to make the cave system accessible to tourists was performed by the New Deal-era Civilian Conservation Corps.

It was disbanded as a national monument on August 24, 1937, and transferred to the state of Montana. The site was formally dedicated as a state park in 1941; Montana's first state park.

Geology

Lewis and Clark Caverns was dissolved by slightly acidic groundwater in tilted beds of the Madison Limestone of Mississippian age. Most of the cave was probably excavated during the ice ages, a time of much greater water supply than today. This limestone was formed by calcium rich organisms that died in a sea that was present around 325 and 365 million years ago. Layer upon layer of organisms stacked on each other and compacted to form this rock group. Reddish sandstone, known as the Amsden, laid down in the Pennsylvanian age was uplifted to current heights during the Laramide Orogeny around 70 million years ago. This uplift constructed joints in the Madison Limestone that would later become caves, such as the Lewis and Clark Caverns.

External links

• Lewis and Clark Caverns State Park