This type of cephalopod began in the Devonian and became the fore-runner of the Mesozoic ammonites. A few species occur in the Devonian, Mississippian, and Pennsylvanian rocks of Iowa. The relationships and significance of these are pointed out.
Proceedings of the Iowa Academy of Science
©1924 Iowa Academy of Science, Inc.
Thomas, A. O.
"Some Goniatites from the Paleozoic of Iowa,"
Proceedings of the Iowa Academy of Science, 31(1), 340-340.
Available at: https://scholarworks.uni.edu/pias/vol31/iss1/107