The principal coal-bearing formation of Iowa and other parts of the western interior basin is the lower coal measures, or Des Moines series as it is now termed. Although the formation has been long recognized in practically its present geologic limits it has been only very recently that any attempt has been made to even suggest subdivisions of the series. It is to these minor distinctive parts that have been made out clearly in southwest Missouri and the adjoining portions of Kansas that attention is directed.
Proceedings of the Iowa Academy of Sciences
©1896 Iowa Academy of Science, Inc.
Keyes, Charles R.
"Stages of the Des Moines, or Chief Coal Bearing Series of Kansas and Southwest Missouri and Their Equivalents in Iowa,"
Proceedings of the Iowa Academy of Science, 4(1), 22-25.
Available at: https://scholarworks.uni.edu/pias/vol4/iss1/6