Abstract Knob Lick Mountain, in the eastern part of the St.Francois Mountains, is about 9.5 mi ( 15.2 km) south of Farmington, in St.Francois County, Missouri (Wachita Mountain 7½-minute Quadrangle). Rising to agentle elevation of 1,333 ft (400 m) above sea level, Knob Lick Mountain may be reached by following Knob Lick Tower Road for 1.1 mi (1.75 km) west of its junction with U.S. 67, just south of the village of Knob Lick (Fig. la), to the parking lot by the lookout tower a top Knob Lick Mountain (NE¼NE¼SE¼, Sec.8, T.34N., R.6E.). A panoramic view of the St. Francois Mountains is afforded from the bald, 100ft (30 m) south of the lookout tower. The intrusive contact of granite with rhyolite is exposed in an abandoned granite quarry, marked on Figure la (SW¼NE¼NE¼, Sec.8, T.34N., R.6E.), about 2,000 ft (600m) northwest from the lookout tower. Access to the quarry is provided by the old ridge road; walk 2,000 ft (600 m) due northwest from the lookout tower on old ridge road, then 200 ft (60 m) due east through the woods to the quarry. Visit of this site involves about a 1.5-hour hike. The site is on public land.

Abstract Burnsville Cove in Bath and Highland Counties (Virginia, USA) is a karst region in the Valley and Ridge Province of the Appalachian Mountains. The region contains many caves in Silurian to Devonian limestone, and is well suited for examining geologic controls on cave location and cave passage morphology. In Burnsville Cove, many caves are located preferentially near the axes of synclines and anticlines. For example, Butler Cave is an elongate cave where the trunk channel follows the axis of Sinking Creek syncline and most of the side passages follow joints at right angles to the syncline axis. In contrast, the Water Sinks Subway Cave, Owl Cave, and Helictite Cave have abundant maze patterns, and are located near the axis of Chestnut Ridge anticline. The maze patterns may be related to fact that the anticline axis is the site of the greatest amount of flexure, leading to more joints and (or) greater enlargement of joints. Many of the larger caves of Burnsville Cove (e.g., Breathing Cave, Butler Cave-Sinking Creek Cave System, lower parts of the Water Sinks Cave System) are developed in the Silurian Tonoloway Limestone, the stratigraphic unit with the greatest surface exposure in the area. Other caves are developed in the Silurian to Devonian Keyser Limestone of the Helderberg Group (e.g., Owl Cave, upper parts of the Water Sinks Cave System) and in the Devonian Shriver Chert and (or) Licking Creek Limestone of the Helderberg Group (e.g., Helictite Cave). Within the Tonoloway Limestone, the larger caves are developed in the lower member of the Tonoloway Limestone immediately below a bed of silica-cemented sandstone. In contrast, the larger caves in the Keyser Limestone are located preferentially in limestone beds containing stromatoporoid reefs, and some of the larger caves in the Licking Creek Limestone are located in beds of cherty limestone below the Devonian Oris-kany Sandstone. Geologic controls on cave passage morphology include joints, bedding planes, and folds. The influence of joints results in tall and narrow cave passages, whereas the influence of bedding planes results in cave passages with flat ceilings and (or) floors. The influence of folds is less common, but a few cave passages follow fold axes and have distinctive arched ceilings.

ABSTRACT This field trip focuses on the geology of the central Appalachian Valley and Ridge province near Harrisonburg, Virginia, USA. Recent geologic mapping utilizing 1-m resolution lidar data has revealed new insights into the Paleozoic stratigraphy, structural geology, and Neogene landscape evolution of the region. The detailed mapping reveals the presence of the Big Spring Station Member and multiple thrombolite zones in the Cambrian Conococheague Formation extending as far south as the Briery Branch 7.5 min quadrangle, providing insights into Late Cambrian sea-level fluctuations. Multiple outcrop exposures in the study area of this guidebook confirm recent work in Pennsylvania, USA, showing that the Ordovician Reedsville Shale overlies the Martinsburg Formation and that the two are distinct and mappable as separate formations rather than laterally equivalent units as previously interpreted. Our work extends the Silurian Williamsport Sandstone into Shenandoah County, Virginia, and describes its facies relationships with the Bloomsburg Formation along strike and across the Adams Run anticline. Mapping within the thick Devonian siliciclastic sequence reveals the presence of the Mahantango Formation on the western limb of Supin Lick syncline and illustrates its complex facies relationship with the Millboro Shale. In addition, we highlight new mapping criteria for the Brallier and Foreknobs Formations and demonstrate how the specific changes to the placement of the contact between them addresses previous challenges in their differentiation. We present cosmogenic burial ages of broad alluvial fan sediments in the Shenandoah Valley near Timberville and Briery Branch, Virginia, and erosion rates estimated for the Briery Branch stream basin. Both analyses provide new constraints on the timing of landscape evolution and karst development since the middle Pliocene. This field guide also highlights some significant structural features within the North Mountain fault zone, such as evidence of imbricated thrust sheets cut by cross-strike faults that have been exploited by Eocene igneous intrusions. Map-scale horses of Silurian and Ordovician rocks hold up ridges that are oblique to the regional strike. Deformation internal to one of these horse blocks is shown to be non-coaxial with respect to the main regional northwest directed transport.

Location Bald Mountain is located in the southeast corner of the Fort Miller 7½-minute Quadrangle, Washington County, eastern New York. Access is gained via New York 40 north from Greenwich, New York (Fig. 1). A paved secondary road (Bald Mountain Road) leads past the quarries on the west side of the mountain, and the quarry faces can be reached by walking along an overgrowngravel track (entered near the intersection of Bald Mountainand Lick Springs roads). The quarries are abandoned, butadjacent landowners should be notified of your intentions. Schaghticoke Gorge is located south of Bald Mountain in the Schaghticoke 7½-minute Quadrangle at Schaghticoke, New York. Access is also from New York 40 at Chestnut Street on thesouth side of the village. A dirt road is followed from the villagestreet to the lower gorge of the Hoosick River (Fig. 1). The mainexposures here lie in the river bottom, and are therefore best seenin the late summer and fall. The river bottom is public domain, but cars should not be driven over the old concrete bridge at theriver (see Fig. 4), as this is owned by the power company.