Location The Mapleton Formation outcrops in a small area in the Presque Isle 15-minute Quadrangle west of Presque Isle, Maine, which lies along U.S. 1, 42 mi (67 km) north of the terminus of I-95 at Houlton. Stops are located along, and north of, Maine 163, an east-west highway from Presque Isle, through Mapleton, to Ashland. Stop 1 is a roadcut on the north side of Maine 163, 2.6 mi (4.2 km) west from the junction of U.S. 1 and Maine 163 in downtown Presque Isle. The exposures of Stop 1 are on a curve near the crest of a hill, so care should be exercised in parking and during study of the rocks. Stop 2 is reached by driving 1.0 mi (1.6 km) west on Maine 163 from Stop 1 to a gravel road to the north. Travel the gravel road 1.0 mi (1.6 km) to the second possible right turn to the east; drive east for 0.5 mi (0.7 km) and park. The outcrops of Stop 2 are located in a small flagstone quarry in a pasture on the south side of the road. Permission should be obtained from the owners.

Abstract The middle Eocene Tyee Formation was deposited in the Oregon Coast Range fore-arc basin (Figure 1). Heller and Ryberg (1983) and Ryu and Niem (1999) describe the Tyee Formation as part of a 6-km (3.7-mi)-thick package of sedimentary rocks that rests unconformably on the Paleocene Siletz River Volcanics (Figure 2). The Umpqua Arch (Figure 1) appears to have influenced deposition of the Tyee and divided the basin into two sub basins. Field mapping by chan and Dott (1983) and Heller and Dickinson (1985) suggests that the Tyee depositonal system includes fluvial and deltaic deposits to the south and that this system prograded to the north through time. Outcrops of the middle Eocene Tyee Formation along Highway 20, west of Corvallis, Oregon, display facies that are characteristic of the distal end of a sand-rich basin-floor fan. This area is more than 100 km (60 mi) basinward of slope and deltaic deposits of the Tyee Formation (Figures 1 and 3). A series of road cuts along Highway 20 exposes up to 460 m (1500 ft) of strike section that shows no evidence of channelization (Figure 4). The primary sedimentary facies here are relatively thick (1-3 m [3-10 ft]) beds of massive sandstones (Ta). These beds are, in many cases, capped by thin (0.2-0.6-m [0.7-2.0-ft]-thick) beds of organic-rich, muddy, fine-grained sandstones that contain rip-up clasts (Figures 5 - 7). We interpreted these muddy beds as slurry deposits (sensu Lowe and Guy, 2000), that is, deposits that record a flow transitional between turbidity currents and debris flows.

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.