Abstract The Benton and Broken Bow uplifts form the central core of the Ouachita Mountains of Arkansas and Oklahoma, respectively (Plate 8; Fig. 1). These uplifts are made up of complexly deformed, early to middle Paleozoic rocks and constitute the largest exposures of the Upper Cambrian to Mississippian, preorogenic strata of the Ouachita folded belt (Lowe, this volume). The oldest formation is the partly exposed Collier Shale, and the youngest is the Devonian to Mississippian Arkansas Novaculite (Ethington and others, this volume). Also described in this chapter are regions of Carboniferous orogenic strata that flank the older rocks of the uplifts.

Abstract Beavers Bend State Park is located approximately 10 mi (16 km) north of Broken Bow, on U.S. 259A. In this park the Mountain Fork River has cut an entrenched meander loop into the Middle Paleozoic flank sequence of the Broken Bow Uplift (Fig. 1). As such, this is a convenient locality to examine the stratigraphic sequence and the structural style of the central uplift of the Ouachita Mountains of Oklahoma. Within the park, U.S. 259A forms a loop east of U.S. 259 (Fig. 1). There are several good hiking trails; therefore, many of these stops will involve light hiking in order to examine the sequence. Also, detailed maps are provided in Figures 1 and 3 in the hope that interested people will hike independently to study the anatomy of these structures. The stratigraphic sequence (Site 45) is examined in two stages. The Womble Shale through the Blaylock Sandstone are discussed at the Stephens Gap Area (Locality 5). The Blaylock Sandstone up to the Lower Stanley Shale is reviewed near the Power Station (Locality 2).