CARBONIFEROUS PLANTS FROM MAZON CREEK, ILLINOIS: A PALEONTOLOGICAL LEGACY OF 19TH CENTURY COAL MINING

The search for coal in the American Midwest in the 1800s led to the discovery of several important fossiliferous localities in Carboniferous-age strata. Among the best-known sites are Linton, Ohio, and the Mazon Creek area, Illinois. Fossils have been collected from siderite concretions at Mazon Creek and surrounding areas of northern Illinois since about 1857. They were discovered in connection with the Colchester (No. 2) coal seam, which extends from Indiana to Oklahoma. The concretions occur in the Francis Creek Shale Member of the Carbondale Formation, which overlies the coal seam. Early collectors, including Joseph Even, Joseph Carr, Samuel Strong, and Homer Hill, provided specimens for description to paleontologists such as F. B. Meek and A.H. Worthen, who described animal fossils, and Leo Lesquereux, who described plant fossils.

The earliest comprehensive report of plants from the original Mazon Creek locality in Grundy, Illinois was published in an Appendix to Lesquereux’s 1866 paper in Geological Survey of Illinois, Volume II, Palaeontology. Many of the specimens from that collection were in the possession of Joseph Even or James Dwight Dana. Some specimens collected in the 1860s and 1870s became part of the geological collection amassed by Rev. Frederick Merrick at Ohio Wesleyan University, Delaware, Ohio. Much of Joseph Even’s collection is thought to have been destroyed in a fire between 1866 and 1868. The Ohio Wesleyan material, therefore, represents an important early reference collection for the Mazon Creek locality. More than 350 specimens, representing at least 12 taxa are present in the collection. The Mazon Creek (Braidwood) flora is today recognized as one of the most diverse of the Paleozoic. Lesquereux originally identified a total of 61 taxa from Mazon Creek concretions.