Type locality and redefinition of name: The name Shelburn Formation was used by Cumings (1922, p. 525, 529) for the rocks included in the "interval between the disconformity above Coal VII and the base of the Merom Sandstone." The name was taken from Shelburn, Sullivan County, Ind., although no type section was designated by Cumings.
Miscorrelation by Shrock and Malott (1929) of the West Franklin Limestone Member, which is at the top of the Shelburn Formation of present definition, resulted in misuse of the name Shelburn. The name was used by Logan (1932) in southern Indiana as a group name for rocks extending to the top of his Ditney Formation, but in Sullivan County the name was used for rocks extending to the top of the Livingston Limestone Member (Bond Formation) (Malott, 1948, p. 125-141; Wier and Esarey, 1951, pl. 4). The Shelburn Formation was defined by Wier and Gray (1961) and Wier (1961, 1965) to include rocks from the top of the Danville Coal Member of the Dugger Formation to the top of the West Franklin Limestone Member. The term Shelburn as thus defined includes only the lower part of the rocks that Cumings originally called the Shelburn Formation in Sullivan County but is the same as the Shelburn Formation that he recognized in Gibson and Vanderburgh Counties to the south.
Description: The Shelburn Formation includes the Busseron Sandstone, Pirtle Coal, and West Franklin Limestone Members, unnamed beds of shale, siltstone, and sandstone, and thin discontinuous beds of coal, clay, and limestone. The formation ranges from 50 to 250 feet (15 to 76 m) in thickness and is mainly composed of shale and siltstone and sandstone.
The Shelburn Formation crops out from along the Ohio River in Vanderburgh and Posey Counties northward to Vigo and Vermillion Counties.
Correlation: The Shelburn is correlative with the lower parts of the Modesto Formation in Illinois and of the Sturgis Formation in Kentucky.