National Geographic : 1964 Jun
Determined caver, his elbows in mud and water, squeezes from a 15-foot long crawlway in Aitkin Cave, Pennsylvania. Straining toes push an adventurer into a tiny slit in Gage Caverns, New York. Such passages lure explorers on with visions of undiscovered wonders. Deep mud challenges a struggling team in Car roll Cave in Missouri's Ozarks. Flash floods at times fill the mouth.