ABSTRACT Fallingwater is a UNESCO World Heritage Site that showcases a unique organic architectural design by Frank Lloyd Wright. Rising from bedrock in Mill Run, Pennsylvania, USA, Fallingwater incorporates large boulders into interior living spaces and is oriented with the geometry of a landscape created by the interplay of mountain and climate. Built to showcase local sandstone, Fallingwater is of the terrain. Building stone was quarried near the house from a 2-m-thick zone of quartzose medium to thin-bedded, fine- to very fine-grained sandstones in the Pennsylvanian upper Pottsville Formation. The building stone has abundant trace fossils and ripple marks, and is interpreted to have been deposited in shoreface environments with some tidal influence, or possibly in tidal flat environments. The house rests on sandstone bedrock of the Homewood sandstone, a Middle Pennsylvanian unit within the upper Pottsville Formation. At Fallingwater, the Homewood sandstone is interpreted to fill an incised valley with coarse, fluvial sandstones common in the lower part of the valley fill and finer-grained fluvial sandstones with possible evidence of marine or brackish influence in the upper fill. The Fallingwater building stone unit overlies the Homewood sandstone, above an interpreted marine flooding surface. Thickening of the Homewood sandstone in synclines suggests that deposition was influenced by Alleghanian deformation. Natural fractures in competent bedrock controlled the orientation of Bear Run at Fallingwater, and the fit of the house within the three-dimensional landscape of the valley, stream, and waterfall. Variation in natural fractures in bedded versus massive sandstone layers appears to have controlled the azimuths of the edges of the waterfalls at Fallingwater. Creation of the Fallingwater sandstone member of the Pottsville Formation is proposed.

Abstract Even before 1800, geological resources such as chert, iron, limestone, and coal were being utilized from the Pennsylvanian rocks of eastern Ohio and western Pennsylvania. These materials were of great interest to the early geologists of the region. This field trip discusses these products in the context of early grain milling, iron furnaces, and allied industries of Ohio and Pennsylvania in the late eighteenth and early nineteenth century, with a focus on two publicly accessible sites: McConnells Mill Park in western Pennsylvania, and Mill Creek Park in eastern Ohio. These parks contain publicly accessible gristmills and iron furnaces, and outcrops. We also provide new observations on cultural materials related to these industries, especially iron-furnace slag and millstones.

Abstract Even before 1800, geological resources such as chert, iron, limestone, and coal were being utilized from the Pennsylvanian rocks of eastern Ohio and western Pennsylvania. These materials were of great interest to the early geologists of the region. This field trip discusses these products in the context of early grain milling, iron furnaces, and allied industries of Ohio and Pennsylvania in the late eighteenth and early nineteenth century, with a focus on two publicly accessible sites: McConnells Mill Park in western Pennsylvania, and Mill Creek Park in eastern Ohio. These parks contain publicly accessible gristmills and iron furnaces, and outcrops. We also provide new observations on cultural materials related to these industries, especially iron-furnace slag and millstones.

ABSTRACT The city of Youngstown, the county seat of Mahoning County, is situated along the Mahoning River in northeastern Ohio, USA. Its early industrial growth was due to the ready availability of iron ore, limestone, abundant forests, and coal, all used for production of iron and then steel during the last two centuries. Local Massillon sandstone and Vanport limestone from Ohio and western Pennsylvania were used to construct mansions and other structures in the nineteenth century. By the early 1900s, other stones including Berea sandstone from Ohio, and sedimentary, metamorphic, and intrusive igneous stones quarried at other sites in North America and Europe, were being utilized as dimension stone in Youngstown. This guide briefly reviews the geological and cultural setting of Youngstown, and describes the building, decorative, and monumental stones used for a variety of structures in downtown Youngstown, with emphasis on stone used for the exterior and interior of major structures. Sites include the Butler Institute of American Art, which is clad with marble and incorporates an assortment of other stone inside and outside of the complex, and St. Columba Cathedral, whose limestone is known commercially as Mankato ( Kasota ) stone and is full of fossil burrows, as well as a sampling of stones used in beautiful Oak Hill Cemetery.