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.

Abstract An integrated approach, involving nearly all available biostratigraphic data, event and sequence stratigraphy, has been utilized in correlation of the Middle Devonian (latest Eifelian–Givetian) Hamilton Group and equivalent strata in north-central North America. This approach permits high-resolution correlation of strata equivalent to the Oatka Creek (upper Marcellus), Skaneateles, Ludlowville and Moscow Formations from New York into sections bordering the Michigan Basin in Ontario, Canada, as well as southern Michigan, northern Ohio and Indiana, USA. Most member and submember-scale units, herein slightly redefined and interpreted as 3rd and 4th order sequences, respectively, and their bounding condensed beds can be correlated regionally. Moreover, many faunal patterns also persist across this region, which, together with sequence stratigraphy, provides a bridge for correlation into the Michigan Basin. The detailed stratigraphy presented herein permits a more-resolved understanding of far-field tectonics, eustasy and biotic responses during the Middle Devonian. Allocyclic processes, primarily eustasy, played a key role in generating persistent sedimentary cycles. Episodes of rapid mud sedimentation occurred over large areas of the cratonic interior, distal to Acadian source terrains. The major Algonquin–Findlay Arch, which presently separates the Michigan Basin from the Appalachian foreland basin, was not present during deposition of these strata. Conversely, a roughly north–south trending region, running approximately through present-day Cleveland, Ohio, was first a local subsiding area during late Eifelian–early Givetian time and then underwent topographic inversion to form a local arch at which upper Hamilton units were condensed and then bevelled during the later Givetian; we infer that this feature may represent a migrating forebulge. Finally, fossil biotas do not show strong partitioning into Appalachian and Michigan basin faunal subprovinces during the early Givetian, as there appears to have been no physical barrier to migration at least in the study area. However, Hamilton-equivalent strata in the most proximal portion of the Appalachian Basin do show a relatively minor admixture of typical Michigan Basin taxa with normal Hamilton forms.