Abstract This field guide focuses on key outcrops that highlight recent nomenclatorial changes of Early Silurian strata in western Ohio (e.g., Dayton Formation, Osgood Formation, Laurel Formation, Lewisburg Formation, Massie Formation, Euphemia Dolomite), as well as the Brassfield Formation and Springfield Dolomite. The field trip begins near the apex of the Cincinnati/Findlay Arch at a quarry in Ludlow Falls, Ohio, and ends at a more offshore position to the southeast, near Clifton, Ohio. Recent conodont biostratigraphic and δ 13 C carb chemostratigraphic data for many of those formations at the field trip localities clearly demonstrate coeval stratigraphic patterns present throughout western Ohio that were previously obscured due to prior inconsistent lithostratigraphic terminology and correlation. Those data also help to show important differences in stratigraphic patterns in western Ohio. Strata correlative to the Lee Creek Formation are recognized for the first time near the apex of the Cincinnati/Findlay Arch in western Ohio in West Milton, Ohio, and are tentatively identified as that formation. At the same locality the Dayton is shown to be completely absent, and the Osgood Formation overlies a thin unit tentatively identified as the Lee Creek Formation and underlying Brassfield Formation. The Springfield Dolomite at the Barrett Paving Materials Ludlow Quarry in Ludlow Falls, Ohio, contains trilobites of the Gravicalymene celebra Association, one of the most taxonomi-cally diverse and geographically widespread trilobite associations in the Silurian of North America. Pentamerid brachiopods occur with molts of Gravicalymene celebra in the Springfield there, suggesting an environmental complexity not seen elsewhere; pentamerids are not found in strata containing the Gravicalymene celebra Association in most other areas of the Midwest.

Abstract This field trip explores the role of geology in the origins and production of a distinctly American distilled spirit. Bourbon whiskey originated in the late 1700s and early 1800s in the Bluegrass region of north-central Kentucky. The Inner Bluegrass is marked by fertile, residual soils developed on karstified Ordovician limestones. Corn was grown, ground, fermented, and distilled to yield a high-value product that would not spoil. The chemistry of limestone water (dilute calcium-bicarbonate type with near-neutral pH) limits dissolved iron and promotes fermentation. Many farms and settlements were located near perennial springs, whose relatively cool temperatures (~13–15 °C) facilitated condensation of steam during distillation. We will visit three historically significant springs. Royal Spring in Georgetown was an early site of whiskey production and is one of the few springs in Kentucky still used for municipal water supply. McConnell Springs was the purported site of Lexington’s founding and occupies a karst window in which distilleries once operated. Cove Spring in Frankfort was the site of the first public water supply west of the Allegheny Mountains. We will also tour two distilleries: Woodford Reserve (among the oldest and smallest in the state, and a National Historic Landmark) and Four Roses (listed on the National Register of Historic Places).

Abstract The objective of this field trip is to examine variability in stream systems in west-central Ohio at different time and space scales. Scales of study range from watershed changes over 10 3 –10 4 years as drainage networks are established during glacial retreat, to reach-scale changes in tributary streams in response to human impacts and land use change over 10 1 –10 2 years, to diurnal and event-driven changes in water quality over 10 –2 to 10 –3 years. Drainage network changes in the Little Miami River and Mad River systems occurred through stream capture and were dependent on the location of early meltwater channels relative to ice lobe position and relict bedrock topography. At the reach scale, channel morphology (width, depth, slope, shape, and pattern) is dependent on mean discharge of water and sediment to the reach. Tributary streams to the Little Miami River, Mad River, and Buck Creek illustrate the impact that historic changes in land use, water and sediment discharge, channelization, and straightening of stream reaches have had on channel morphology and vertical stability. At the cross-section scale, flow characteristics, including stream stage and physical water quality parameters (temperature, pH, specific conductivity, oxidation-reduction potential, dissolved oxygen, and turbidity), are being measured on Buck Creek and Beaver Creek. Though some characteristics change diurnally in response to internal stream processes, event-based changes in response to stormflow reflect source area contributions of runoff and sediment.

Abstract This article is aimed at providing an overview of the geology of the Dayton region to those who seek an introduction to Dayton’s geological story. The oldest rocks exposed in the area are Ordovician (Katian Stage, Cincinnatian Series in local North American usage) in age, and are world famous for the quantity and quality of their fossils. Unconformably overlying the Ordovician strata are Silurian (Llandovery–Wenlock Series) dolomites, limestones, and shales, which represent tropical seas that were at times rich in crinoids, corals, brachiopods, and other invertebrates. A large time gap (unconformity) in the rock record of some 420+ million years occurs between the Silurian and the Pleistocene “Ice Age” deposits of the area. Significant changes to the natural environment in the Dayton area have occurred during the Anthropocene. A number of localities that can be reached within about 30–40 minutes from downtown Dayton are described. This is effectively Montgomery County and adjacent counties. As such this treatment is brief and not meant as a compendium but as an introduction and outline of Dayton’s geology and geological history. The localities selected illustrate Dayton’s geological heritage, from the Ordovician to the Pleistocene, while several of the area’s distinctive natural landmarks are discussed. A number of the landforms are expressions of the Niagara Escarpment, where resistant Silurian limestones and dolomites overlie less resistant older rocks.

Abstract This walking tour will consider local geology, touch on local history, and focus on the building stones used in downtown Dayton. Building stones and construction materials used along Main Street are the main interest. Special attention will be paid to “Dayton’s own,” the Dayton limestone—a stone considered by State Geologist Edward Orton in the second half of the nineteenth century ( Orton, 1870 , 1893 ) as one of Ohio’s finest building stones. The Dayton Formation (Dayton limestone) was used extensively as a building stone in the Dayton area (and farther afield) during the nineteenth and early years of the twentieth centuries during the growth of Dayton. Perhaps the zenith of the Dayton limestone building-stone industry is characterized by the Old Courthouse (1850), an important building in the Greek-Revival architectural-style that saw the use of Dayton limestone not only for the exterior of the building but also, unusually, and perhaps with a little too much enthusiasm, for slabs of limestone for the roof. This building has much local historical significance— both Presidents Abraham Lincoln and John F. Kennedy addressed the public from its steps. Dayton limestone was used for the commemorative stone from the State of Ohio, installed in 1850, inside the Washington Memorial, Washington, D.C., and for part of the “Ohio House” built for the International Exhibition at Fairmount Park, Philadelphia, Pennsylvania, commemorating the centennial of the signing of the Declaration of Independence in 1876. Use of the stone is also documented in Cincinnati, Columbus, and Chicago. Recent developments along East Monument Avenue and Patterson Boulevard— RiverScape and the Patterson Boulevard canal walk—as well as some of the buildings, will be discussed. The “Great Dayton Flood” of 1913 probably resulted in excess of four hundred deaths along the Great Miami River valley and its watershed. The Miami Conservancy District oversees the flood-prevention scheme that developed after the 1913 flood; their headquarters are housed in a building that overlooks the Great Miami River in downtown Dayton. Flood-prevention modifications to the Great Miami River can be seen adjacent to downtown.

Abstract This field trip will be to a working limestone quarry near Paulding, Paulding County, Ohio, a little over 100 mi (160 km) north of Dayton, Ohio. The quarry is working Middle Devonian strata: the Dundee Formation and overlying Silica Formation and Tenmile Creek Dolomite of the Traverse Group. The focus of the trip will be the fossiliferous Silica Formation (Silica shale)—collecting from blocks of rock from recent quarry blasting. At Paulding, the thickness of the Silica Formation is reduced compared to farther north in the vicinity of Sylvania, Ohio. The most common fossils are brachiopods, bryozoans, corals, and trilobites. The visit will be timed with a recent blasting of the quarry’s western rock face. Be aware that the terrain is uneven, and care must be exercised while fossil collecting. The quarry and adjacent cement plant at Paulding are operated by LaFarge.

Abstract This volume, produced in conjunction with the GSA North-Central Section Meeting held in Dayton, Ohio, April 2012, has a mix of papers, ranging from stratigraphy, paleontology, and hydrogeology, to geomorphology, drainage basins, and building stones. The geographic spread of the chapters focuses mainly on an area bounded by those counties adjacent to Montgomery County, but also extends beyond-from Paulding County in the north to Georgetown, Kentucky, in the south. Topics include the Silurian stratigraphy of southwestern Ohio, drainage basins of the Mad River and Little Miami River, the relationship between geology and groundwater of the Inner Bluegrass Region, Kentucky (and its connection to the distilling and aging of bourbon), and the building stones of Dayton, as well as an introduction to the geology of the Dayton area.