When I was a kid my favorite Saturday morning television show was the groovy Land of the Lost. True the special effects weren't all that special or believable, but it was engaging all the same. Especially scary was in the opening sequence went the tyrannosaurus rex's puppet mouth came at the scream in a roar.
For those of you who may have lived in a cave during the mid-70's . . . The premise of the show is that Rick Marshall (the dad) is a park ranger who takes his two kids, Will and Holly, on a rafting trip down a river. During the trip, an earthquake occurs which somehow opens up a rift in time, propelling the Marshalls into a land populated by dinosaurs, ape-men, and the dreaded Sleestak.