The Sleestak God

Written by David Gerrold and directed by Dennis Steinmetz, it first aired in the United States on September 14, 1974 on NBC.

Using Morse code by reflecting sunlight from a mirror worn on a necklace, Will messages their discovery to Rick, who agrees to meet with them in the jungle.

Cha-Ka finds Rick and quickly leads him to the ruins, where they are intimidated by an allosaur (dubbed earlier "Big Alice" by Holly).

Rick and Cha-Ka enter the ruins and fend off the Sleestak with a torch, which accidentally falls into the pit and sets the creature within on fire.

[1] Film historian Hal Erickson praised "The Sleestak God" for keeping Cha-Ka's leg broken from the previous episode, saying "That's what we mean by good continuity.