While making a study of the Keokuk beds in southeastern Iowa during the field season of 1911, the writer was attracted by certain irregularities at the contact of those beds with the overlying strata. The Keokuk, instead of being followed always by the Warsaw, which is the normal order, was found to be succeeded above sometimes by a dense, white, fine-grained, non-fossiliferous limestone, and sometimes by a fossiliferous magnesian limestone or by an arenaceous phase into which it grades laterally.
Proceedings of the Iowa Academy of Science
©1912 Iowa Academy of Science, Inc.
Van Tuyl, Francis M.
"The Salem Limestone and Its Stratigraphic Relation in Southeastern Iowa,"
Proceedings of the Iowa Academy of Science, 19(1), 167-168.
Available at: https://scholarworks.uni.edu/pias/vol19/iss1/28