The type section of the Sweetland Creek Shale in Muscatine County has yielded a sequence of five distinct conodont faunas which correspond almost exactly to a zonation of the Upper Devonian Frasnian Stage by Ziegler (1962 b) in the Rhineland. In addition, the nearby Campbell's Run section has produced the lower three faunas. The Sweetland Creek is equivalent in part to the Independence Formation, and is regarded as representing the southeastern extension of that unit in its true stratigraphic position above the Cedar Valley Formation.
Proceedings of the Iowa Academy of Science
©1962 Iowa Academy of Science, Inc.
Klapper, Gilbert and Furnish, W. M.
"Conodont Zonation of the Early Upper Devonian in Eastern Iowa,"
Proceedings of the Iowa Academy of Science, 69(1), 400-410.
Available at: https://scholarworks.uni.edu/pias/vol69/iss1/64