The series premiered in
1975. Stopped in 1976 after 11 issues.
A family consisting of science
teacher John Butler, his wife Kim, and their children Katie and
Greg capsizes during a rafting trip on the South American Amazon
River. They are helped by some prehistoric cave people led by
Gorok, who all live in a forgotten valley filled with menacing
animals. The family's goals are to survive the many dangers and
to return to civilization.
The series is a spinoff from a cartoon TV series
that ran from 1974 to 1976 (16 episodes).