Natural Bridge Caverns, discovered on March 27, 1960, by four students of St. Mary's University in San Antonio, were named for the rock bridge that marks the entrance and were dedicated on August 5, 1964, by Governor John Connally. Of Early Cretaceous age and still forming, the site has yielded artifacts from 5,000 B.C., human remains at least 8,000 years old, and Indian campsites.