On 23 November 2011 I entered the upstream entrance of Twin Cave to do a snapshot assessment of the condition of the cave community. The cave entrance is in the floor of a sinkhole and allows rapid access to the main stream passage of the Donaldson (Shawnee) Cave System after climbing down a breakdown slope.
Bruce Bowman
Bob Decker
Keith Dunlap
Kriste Lindberg
Steve Lockwood
Everett Pulliam
Tom Rea
Tom Sollman
Bruce Trotter
Bob Vandeventer
Central Indiana Grotto
National Speleological Foundation