Some of the best special effects of the 1950s are the highlights of this half-decent Saturday matinee adventure flick. The prehistoric beasts here are guys in suits and monitor lizards, but they look convincing as they tower over tiny fleeing humans on the wide Cinemascope screen. The script is as skimpy as a Wicked Weasel bikini, but at least it’s short. A US military crew explores Antarctica and one of the helicopters gets so lost that it winds up marooned in a crater that leads to an Edgar Rice Burroughs-style tropical land out of a time. The wonderfully named Jock Mahoney plays the sturdy team leader, top man of action and resident science expert. B-movie stalwart Shirley Patterson, in one of her last films, plays the damsel in frequent distress and Mr. Mahoney’s love interest.