RELATIONSHIPS OF MIDDLE SILURIAN STRATA IN OHIO AND WEST VIRGINIA1

The Estill, Bisher, Lilley, and Peebles Formations crop out in Adams and Highland Counties, Ohio. All these units can be traced several miles eastward into the subsurface of the Appalachian Basin. Farther east, the Peebles and Lilley strata lose their distinctive lithology and become part of subsurface beds identified as Lockport by previous investiga-tors. The Lockport beds intertongue with carbonates of the McKenzie Formation in eastern Ohio and western West Virginia. The "Clinton shale " of the driller shows a three-fold division in the subsurface of central Ohio: 1) upper dolomitic shales, 2) intermediate silty or arenaceous carbonates, and 3) lower green and brown clay shales. The upper and middle units can be traced from central Ohio southwestward into the Bisher, and the lower unit into the Estill Shale of southern Ohio. Eastward, near the Ohio-West Virginia boundary, the middle unit of the "Clinton shale " shows a facies relationship with the Keefer Sandstone. The lower unit of the "Clinton shale " can be traced eastward into the upper half of the Rose Hill Formation in West Virginia