Published online by Cambridge University Press: 14 July 2015
Representatives of 12 conodont species, including Oulodus equirectus n. sp., have been recovered from the Silurian Lilley Formation, Lilley–Peebles transition unit, and Peebles Dolomite at six localities in southern Ohio. The Lilley, Lilley–Peebles transition unit, and Peebles belong in the Kockelella ranuliformis–K. amsdeni to Ozarkodina? crassa Chronozone and are late early to middle Wenlockian in age.
The Lilley is conformable and transitional with the underlying Bisher Formation and overlying Peebles. The unconformity between the upper Niagaran Peebles and overlying lower Salinan Greenfield Dolomite represents middle Wenlockian to late Ludlovian or early Pridolian time.
The Lilley, Lilley–Peebles transition unit, and Peebles were deposited in a gradually shoaling sea that was controlled by eustatic sea-level fall during the late early to middle Wenlockian. Uplift along the Cincinnati Arch, probably due to northward tilting of the arch, began during/after deposition of the Peebles in the middle Wenlockian. The combined effects of uplift and eustatic sea-level fall caused the sea to withdraw from southern Ohio. The Peebles was exposed and eroded prior to return of the sea to begin Greenfield deposition in the late Ludlovian or Pridolian (Ozarkodina remscheidensis Chronozone).