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
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