Lava Pit

The Lava Pit, also referred to by Peter Koenig and Harry Potts as the Devil's Cauldron, is a heat source that regularly cycles between low and high levels of lava, which regulate the hibernation cycles of Sleestak. The pit was discovered by the Marshalls in Season 1, Episode 13 "Follow that Dinosaur" after crawling though a tunnel marked by an arrow. Upon arrival, the family discovers to their dismay that Koeing and Potts never found an exit to the Land of the Lost inside the Lost City. The remains of Koeing along with the rest of his journal was found next to the pit.