David A. Riggs:
Beaverhole Lower entrance
David A. Riggs:
P1000942
David A. Riggs:
P1000939
David A. Riggs:
P1000921
David A. Riggs:
Sinks of the Run - Brian
David A. Riggs:
Dunbar Sandstone Mines 080
David A. Riggs:
Elkhorn Mountain 30