In his report on the geology of Lee county Keyes described a fine-grained, compact limestone at the top of the St. Louis formation, resembling lithographic stone in texture. Gordon reported a similar limestone characterized by Spirifer littoni (=Spirifer pellaensis Weller) and Pugnax ottumwa at the same horizon in Van Buren County. Bain subsequently recognized this member in Keokuk County and named it the Pella because of its typical development at the town of this name in the neighboring county of Marion. This name has been adopted by Savage in his geology of Henry County and by Miller in the Marion county report.
Proceedings of the Iowa Academy of Science
©1915 Iowa Academy of Science, Inc.
Weller, Stuart and Van Tuyl, Francis M.
"The Ste. Genevieve Formation and Its Stratigraphic Relations in Southeastern Iowa,"
Proceedings of the Iowa Academy of Science, 22(1), 241-247.
Available at: https://scholarworks.uni.edu/pias/vol22/iss1/31