Spring Mill State Park (GM-34)
Spring Mill's historic impact is matched by the heritage of nature that
the park preserves. Containing some virgin timber, the area is pockmarked
by sinkholes, and nine named caves lie within the park. These features
were formed, and are being modified by rainwater percolating through the
soil down into the underlying limestone. The topography was formed during
the past few million years, but the bedrock originated in seas that
covered Indiana more than 300 million years ago.
Donaldson Cave system and
Hamer Cave are the major caves in the park, and both were intimately
related to the life of the early residents. Both provided water to power
mills; saltpeter for gunpowder was taken from Donaldson; and villagers
butchered meat and cooled perishable foods in both.
Our Hoosier State Beneath Us: