Buffalo Wallow Group,
Type locality and description in Illinois: The Waltersburg Sandstone was named by Stuart Weller (1920a, p. 398) for exposures of a massive cliff-forming sandstone near Waltersburg, Pope County, Ill. The unit is as much as 70 feet (21 m) thick, but it is absent or unrecognizable in many places. In discussing the Waltersburg Formation in the standard Chesterian section, Swann (1963, p. 38) described it as primarily dark shale containing elongate sandstone bodies and 35 to 80 feet (11 to 24 m) thick.
History of name and description in Indiana: In his initial study of outcropping upper Chesterian rocks in Indiana, Malott (1925, p. 108-109) named a thin ledge-forming sandstone the Wickliffe Sandstone. Later he asserted a correlation with the Waltersburg (Malott, 1931, p. 222), and that name came into general use, replacing Wickliffe. Boundaries of the unit were never adequately defined, however (see the discussion of boundary problems under "Tar Springs Formation"), and in a restudy of outcropping upper Chesterian rocks, Gray (1978) did not find need to name a member at this position, which is within the Branchville Formation of surface usage.
In Indiana the term Waltersburg Sandstone is now restricted to subsurface use, where it is commonly applied to lenticular sandstone bodies as much as 60 feet (18 m) thick lying between the Vienna and Menard Limestones. The Waltersburg Sandstone is known from Daviess County southwestward. For Indiana usage the Waltersburg is here assigned to the Buffalo Wallow Group.