Geologic names of Ordovician rock-stratigraphic units exposed in Kentucky

This report summarizes and indexes the current usage of geologic names of exposed rock-stratigraphic units of Ordovician age in Kentucky. The Ordovician rocks crop out mainly in two separate areas in Kentucky (fig. 1). The larger area of outcrop, covering much of the middle part of the state, forms the major part of the Blue Grass region of Kentucky. Outcrops of this region are contiguous with outcrops of Ordovician rocks in southwestern Ohio and southeastern Indiana. The smaller area of fairly continuous outcrops of Ordovician rocks lies south of the Blue Grass region along the Cumberland River and its tributaries. These outcrops are contiguous with outcrops of Ordovician rocks in Tennessee. A few isolated exposures of Ordovician rocks lie outside the areas of continuous outcrop.