Configuration of the buried part of the Teays Valley system across western Ohio, Indiana, and eastern Illinois suggests that the Teays is not a preglacial system, but rather, that it was formed marginal to a major glacier earlier than that which created the Ohio River, probably in similar fashion by consolidating and diverting fragments of older drainages. Pertinent criteria include (1) the relatively straight gorge that (2) crosses at least three regionally high areas with (3) few tributaries that join at grade. Also significant are (4) the depth of the gorge across a broad limestone plateau that has (5) relatively shallow karst development. These features imply a youthful valley system that was destroyed by burial before reaching a mature stage.

Although thousands of drillholes and seismic datum points in Indiana alone detail the bedrock surface and the nature of the unconsolidated deposits that overlie it, many questions remain regarding the evolution of that surface. Fluvial and lacustrine deposits associated with the earliest presently known till in Indiana (>0.8 Ma) fill eastern parts of the Teays gorge. Are there tills of pre-Teays age, and is any part of a pre-Teays valley system identifiable? What stratigraphic criteria distinguish those parts of the Teays that have been reoccupied and incorporated into younger, but now also buried, valley systems? The Blue River Strath of southern Indiana shares many characteristics with the type Teays and the ancestral Kentucky River valley and may be coeval with them; are there other such features? A regional approach to these and related questions should yield results.