The Cretaceous system in Iowa is composed of shales, argillaceous limestones and sandstone, and argillaceous sandstones. The former are generally referred to the Fort Benton horizon of the Colorado, while the latter are placed with the Dakota.
Proceedings of the Iowa Academy of Science
©1927 Iowa Academy of Science, Inc.
Cable, E. J.
"Outcrop of Cretaceous Sandstone in Cherokee County,"
Proceedings of the Iowa Academy of Science, 34(1), 243-245.
Available at: https://scholarworks.uni.edu/pias/vol34/iss1/60