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.

ABSTRACT The physical and fluvial development of the Driftless Area, largely in Wisconsin, has been investigated by James C. Knox and was the subject of a 1982 field trip. This chapter reviews and expands current understanding of the geomorphic history in and adjacent to the Driftless Area in northeast Iowa and southeast Minnesota, and the paleoecology and paleoclimates that were important in the late glacial and Holocene landform development. This information was largely obtained using fossil pollen, plant macrofossils, fossil mammals and insects, and cave speleothem records.

ABSTRACT More than 100 air-fall volcanic tephra beds are currently documented from Devonian strata in the eastern United States. These beds act as key sources of various geological data. These include within-basin to basin-to-basin correlation, globally useful geochronologic age dates, and a relatively detailed, if incomplete, record of Acadian–Neoacadian silicic volcanism. The tephras occur irregularly through the vertical Devonian succession, in clusters of several beds, or scattered as a few to single beds. In this contribution, their vertical and lateral distribution and recent radiometric dates are reviewed. Current unresolved issues include correlation of the classic Eifelian-age (lower Middle Devonian) Tioga tephras and dates related to the age of the Onondaga-Marcellus contact in the Appalachian Basin. Here, we used two approaches to examine the paleovolcanic record of Acadian–Neoacadian silicic magmatism and volcanism. Reexamination of volcanic phenocryst distribution maps from the Tioga tephras indicates not one but four or more volcanic sources along the orogen, between southeastern Pennsylvania and northern North Carolina. Finally, radiometric and relative ages of the sedimentary basin tephras are compared and contrasted with current radiometric ages of igneous rocks from New England. Despite data gaps and biases in both records, their comparisons provide insights into Devonian silicic igneous activity in the eastern United States, and into various issues of recognition, deposition, and preservation of tephras in the sedimentary rock record.

ABSTRACT The glaciated terrain along the northern edge of the Appalachian Plateau in the eastern Finger Lakes of central New York has long been recognized as an important location for meltwater routing and for proglacial lake development in the Great Lakes region. Despite recognition of multiple ice margins formed by the Ontario Lobe of the Laurentide ice sheet during the late Wisconsinan, numerical age control of several margins has been elusive, particularly in regard to regional readvances of the Port Bruce (ca. 16,980–18,000 cal [calibrated] yr B.P.) and Port Huron (ca. 14,300– 16,000 cal yr B.P.) Phases. Utilizing light detection and ranging (LiDAR) terrain models in the eastern Finger Lakes area, we identified and described the Mapleton, Tully, and Labrador Hollow moraines. Associated ice-marginal landforms include push moraines, fans, and hummocky topography. In places, these features intrude into the northern heads of through valleys. Coring of three basins directly associated with these landforms yielded more than 20 samples of boreal tree needles and twigs, and Dryas leaves. Accelerated mass spectrometry (AMS) radiocarbon assay results indicate that poststadial lacustrine sedimentation began at ca. 15,000 cal yr B.P., consistent with ages of the Port Huron Phase.