lsophorus. Edriophus. Maquoketa Formation. Winneshiek County
Two specimens of edrioasteroids have been found in the Maquoketa Formation, Richmond Group, Upper Ordovician of Iowa. This occurrence extends the geographic range of both genera, lsorophus Foerste (1917) and Edriophus Bell (1975) into Iowa which is the westernmost occurrence of these genera formerly recorded only east of Illinois. Isorophus was found in a horizon essentially barren of fossils but Edriophus is coexistent with more common echinoderms of the Maquoketa, including the crinoid genera Carabocrinus and Porocrinus.
Proceedings of the Iowa Academy of Science
©1976 Iowa Academy of Science, Inc.
Bell, B. M.; Strimple, H. L.; and Levorson, C. O.
"Edrioasteroids (Echinodermata) of the Maquoketa Formation of Iowa,"
Proceedings of the Iowa Academy of Science, 83(1), 23-27.
Available at: https://scholarworks.uni.edu/pias/vol83/iss1/6