Cave, New Discovery, survey party on Fossil Avenue
Mammoth Cave National Park; National Park Service
Survey, man with level rod in cave
Mammoth Cave National Park; National Park Service
Survey, man with level rod in cave
Mammoth Cave National Park; National Park Service
Survey, man with level rod in cave
Mammoth Cave National Park; National Park Service
Survey, man with level rod in cave
Mammoth Cave National Park; National Park Service
Scale showing height of cave ceiling, Cox Case
Mammoth Cave National Park; National Park Service
Scale showing height of cave ceiling, Cox Case
Mammoth Cave National Park; National Park Service
Scale showing height of cave ceiling, Cox Case
Mammoth Cave National Park; National Park Service
Scale showing height of cave ceiling, Cox Case
Mammoth Cave National Park; National Park Service
Scale showing height of cave ceiling, Cox Case
Mammoth Cave National Park; National Park Service
Scale showing height of cave ceiling, Cox Case
Mammoth Cave National Park; National Park Service
Cave, survey party at work during opening of end of Fossil Avenue, 1942
Mammoth Cave National Park; National Park Service
Survey, man with wooden rule in cave measuring formation
Mammoth Cave National Park; National Park Service
Survey, man with level rod in cave, showing height of cave
Mammoth Cave National Park; National Park Service
Survey, man with level rod in cave, showing height of cave
Mammoth Cave National Park; National Park Service
Survey, man with level rod in cave, showing height of cave
Mammoth Cave National Park; National Park Service
Survey, man with level rod in cave, showing height of cave
Mammoth Cave National Park; National Park Service
Survey, man with level rod in cave, showing height of cave
Mammoth Cave National Park; National Park Service
Survey, man with level rod in cave, showing height of cave
Mammoth Cave National Park; National Park Service
Survey, man with right arm out in cave passage, showing size of cave
Mammoth Cave National Park; National Park Service
Survey, measuring stalagmite in cave
Mammoth Cave National Park; National Park Service
Cave, column with measuring stick against it
Mammoth Cave National Park; National Park Service
Carl Hanson showing height of ceiling, Cox Case
Mammoth Cave National Park; National Park Service
Carl Hanson showing height of ceiling, Cox Case
Mammoth Cave National Park; National Park Service
Carl Hanson showing width of cave, Cox Case
Mammoth Cave National Park; National Park Service
Survey, measuring broken off formations in cave
Mammoth Cave National Park; National Park Service
Carl Hanson showing height of ceiling, Cox Case
Mammoth Cave National Park; National Park Service
Cave, Carl Hanson measuring height of ceiling, Cox Case
Mammoth Cave National Park; National Park Service
Cave, Carl Hanson measuring height of ceiling, Cox Case
Mammoth Cave National Park; National Park Service
Cave, Carl Hanson measuring height of ceiling, Cox Case
Mammoth Cave National Park; National Park Service
Cave, Carl Hanson measuring height of ceiling, Cox Case
Mammoth Cave National Park; National Park Service
Survey, man with ruler measuring distance across formation
Mammoth Cave National Park; National Park Service
Cave, Carl Hanson measuring height of ceiling, Cox Case
Mammoth Cave National Park; National Park Service
Cave, Carl Hanson measuring height of ceiling, Cox Case
Mammoth Cave National Park; National Park Service
Survey party going into new discovery, 6 NSS members in cave, 1939
Mammoth Cave National Park; National Park Service
Cave, Carl Hanson measuring height of ceiling, Cox Case
Mammoth Cave National Park; National Park Service
Cave, Carl Hanson measuring height of ceiling, Cox Case
Mammoth Cave National Park; National Park Service
Survey, man with light pointed at another man far above him
Mammoth Cave National Park; National Park Service
Survey, man in upper level of cave and another man on lower level giving perspective of cave size
Mammoth Cave National Park; National Park Service
