SECTION 8211 Road to Dumbell Hill at top of escarpment just where road comes off Polecat Bench. 1130 m east of SW Corner, 340 m north of SE Corner of sec 31 T 57N, R98W, Park County, Wyoming. Deaver Reservoir 7½' Quad. UNIT Fort Union Formation: Thickness 5.2 Top of Section Mantua lentil: sandstone; as in Sec. 8210 at 2.52 m, representing the lateral extension of the Mantua lentil. Unit is calcareously cemented and ledge forming with a 0.4 m interbed of carbonaceous shale lying 1 m above its basal contact. 3.04 2.16 Shale: carbonaceous, 5YR 4/1 with limonite staining and plant fragments, becomes papery above 2.68. 2.95 siltstone, cross-laminated, with vertical roots, otherwise as below. 2.87 shale: becomes platey with plant fragments 2.83 shale: gypsiferous, 5GY 6/1 2.46 1.06 2.74 shale: chippy, silty, with poor leaf fragments. 2.42 Siltstone: about 2.5 cm thick .04 2.23 Clay: massive, 10YR 6/2, with vertical and horizontal roots. .19 2.15 Lignite: blocky, black, top 1 cm brown and gypsiferous. Basal contact of Fort Union Formation. .08 Lance Formation: 2.11 Clay: massive, carbonaceous, 10YR 5/2 .04 2.10 Lignite stringer .01 Clay: carbonaceous, 5Y 3/2, slickensided, limonite stained, with root impressions. Interpreted as an underclay of lignite at 2.10. 1.8 1.99 - 1.95 Band of unctuous dark grey (5Y 2/2) clay. .11 Mudstone: fissile, 5Y 6/2 with root casts, carbonaceous material, and limonite joint stains. Plant fragments and roots more common upward. 1.25 1.45 mudstone: chippy .74