(photo by Ljubomir Risteski)

Western Kentucky's Mammoth Cave is the longest cave system on Earth, with 412 miles known and mapped as of fall 2017. The name does not refer to the early discovery of fossil mastodon or mammoth bones here. Rather, the name refers to the immense size of many rooms and passages.

The system has a variety of cave passages: tubular passages, canyon passages, vertical shafts (domepits), keyhole passages, and giant canyon passages.

Sidesaddle Pit is a moderately large vertical shaft that can be viewed during the 2-hour, 2 mile-long Historic Tour. Vertical shafts, also called domepits, are large, silo-shaped, dissolutional features in caves. They form in the vadose zone (above the water table) as downward-moving groundwater dissolves limestone by enlarging joints or joint intersections.

Limestones of the Fredonia Member line the walls of Sidesaddle Pit. The Fredonia is one of many members in the Ste. Genevieve Limestone (upper Middle Mississippian). Vertical grooves called flutes are incised on the walls here. Flutes are vadose dissolutional features on vertical cave walls. Similar to flutes are rills, which are vadose dissolutional features on sloped limestone surfaces

The rubble-covered floor of this domepit appears to bottom out in the lower Ste. Genevieve Limestone (Fredonia Member) or the upper St. Louis Limestone. The pole- or stake-like object on the floor of Sidesaddle Pit was not present 10 years ago. I don't know why the park service hasn't removed it (I've noticed that the American government is very slow and/or nonresponsive to cleaning up vandalism in national parks).