Among a large number of species recently discovered in the lower coal measures near Des Moines are some hitherto unrecognized forms. The following are the descriptions of three of the most important shells.
Proceedings of the Iowa Academy of Sciences
©1890 Iowa Academy of Science, Inc.
Keyes, Charles R.
"Contribution to the Fauna of the Lower Coal Measures of Central Iowa,"
Proceedings of the Iowa Academy of Science, 1(Pt. 2), 22-23.
Available at: https://scholarworks.uni.edu/pias/vol1/iss2/10