Plate 1. Map of Indiana showing locations of type sections, localities, and area for Paleozoic rock units named for Indiana places 682K.

Plate 2. Charts showing Paleozoic rock-unit names used in Indiana: A, Pennsylvanian; B, Mississippian; C, Devonian; D, Silurian; E, Ordovician and Cambrian 1250K.

Figure 1. Chart showing significant developments in nomenclature of the Sanders Group. Modified from Nicoll and Rexroad (1975).

Figure 2. Chart showing correlation of rocks of the Blue River Group with rocks of the formational type areas in Illinois and Missouri. Named beds are not shown.