Notation on back, "Far beneath the earth in the Endless Caverns of New Market, Virginia with the Geiger-Mueller Counter and recording apparatus, Professors J.W. Beams, E.P. Ney, L.B. Snoddy of the Rouss Physical laboratory, University of Virginia, Charlottesville, Virginia, are here shown preparing to descend with the 50-pound apparatus, by means of a rope, an 80 foot subterranean cliff to the cavern's underground stream where recordings were taken of cosmic rays, which, at that depth, had penetrated 180 feet of limestone. This was the deepest point in the caverns so far reached by the scientists. Still other recordings were made in a grotto adjoining "The Underground Cathedral", near the caverns' exit, beneath 20 feet of limestone, and at points beneath 45 feet and 125 feet of limestone, as shown in other photos."
Special Collections, University of Virginia Library, Charlottesville, Va.