Type section: The name Falling Run Member of the Sanderson Formation was first used by Campbell (1946), who designated the type section on Falling Run Creek at the end of Market Street, New Albany, Ind. The type section is in the NW¼SE¼ sec. 3, T.3 S., R. 6 E., Floyd County. The Falling Run was reduced in rank to the status of bed by Lineback (1968, 1970).
Description: The Falling Run Bed consists of sparsely fossiliferous phosphatic nodules in a 0.2-foot-thick (0.06-m) zone near the top of the Clegg Creek Member of the New Albany Shale (Lineback, 1970). The nodules range in shape from spherical to ellipsoidal and are as much as 0.7 foot (0.2 m) long in the elongate forms (Lineback, 1970). Throughout most of southern Indiana the Underwood Bed is not present, so that the Falling Run Bed is directly overlain by the Henryville Bed in most of that part of the state (Lineback, 1968, 1970). In the outcrop area in southeastern Indiana the Falling Run Bed has been traced from Floyd County as far north as Jackson County. Phosphate nodules have been found at a similar stratigraphic position in a core of the New Albany Shale in Dubois County in southwestern Indiana, and according to Cluff and others (1981) the Falling Run Bed is present in southeastern Illinois in a cored section of the New Albany Shale Group in Wayne County and in an exposure of the upper part of the shale in Hardin County.
Correlation: The Falling Run Bed is probably earliest Mississippian in age, although no conclusive evidence has been found (Lineback, 1970). (See also "Clegg Creek Member, Correlation. ")