Pg. vi (chart), 32-36. Poskin Member of Copper Falls Formation. (Follows informal usage of M.D. Johnson, 1986, Wisconsin Geol. Nat. Hist. Survey Inf. Circ., no. 55, 42 p., and M.D. Johnson, 1984, Univ. Wisconsin PhD dissert.) Till and stream sediment. Yellowish red, slightly gravelly to gravelly sandy loam. Thickness up to 50 m. Where exposed, typically underlies loess and overlies sand and gravel; upper and lower contacts are sharp. In southwestern Barron County, overlies sandstone. Interpreted as having been deposited by ice of Superior Lobe flowing southeast during early St. Croix advance. Is older than Sylvan Lake Member and younger than Pokegama Creek Member (new), both of Copper Falls Formation. Age is considered Pleistocene (late Wisconsinan).
Type section: gravel pit on west side of a north-south road, in NE/4 NE/4 SE/4 sec. 25, T. 35 N., R. 12 W., [approx. Lat. 45 deg. 29 min. 10 sec. N., Long. 91 deg. 47 min. 12 sec. W.], Barron 7.5-min quadrangle, Barron Co., northwestern WI.
Named from community of Poskin, Barron Co., [about 8+ mi southwest of type section]; name credited to Mark D. Johnson.
Reference section: gravel pit on north side of WI State Highway 48, in SE/4 SW/4 sec. 14, T. 35 N., R. 12 W., [approx. Lat. 45 deg. 30 min. 39 sec. N., Long. 91 deg. 49 min. 09 sec. W.], southern edge Haugen 7.5-min quadrangle, Barron Co., northwestern WI.
[Additional locality information from USGS historical topographic map collection TopoView, accessed on June 9, 2018.]

Source: Publication.