Most sink holes occur in regions where the underlying rock is dominantly calcareous. They are variously shaped depressions in the surface into which the run-off is carried away as subterranean drainage.
Proceedings of the Iowa Academy of Science
©1920 Iowa Academy of Science, Inc.
Cable, E. J.
"A Note on A Sink Hole,"
Proceedings of the Iowa Academy of Science, 27(1), 181-183.
Available at: https://scholarworks.uni.edu/pias/vol27/iss1/24