1. Notes on the geology of Johnson County, Iowa Author(s): Webster, Clement L., author Publication: [New York?] : [publisher not identified], [1888?] Subject(s): Geological PhenomenaIowa
2. The St. Peter's sandstone Author(s): James, Joseph F. (Joseph Francis), 1857-1897 author Publication: [Cincinnati?] : [publisher not identified], [1894?] Subject(s): Geological PhenomenaMidwestern United States