Age Unit Ft. BARREM-APT. PATUXENT FM. A1.E 10 5 0 Description Interpretation Trash Gravel, Sand, Silt Fluvial Aggredational Sand and silt: medium to light grey, friable sandstone fine to medium-grained planar and trough cross-beds, logs, marcasite concretions. Fluvial; braided stream deposits. Fig. 3 -- Geologic section of the rocks exposed along the Northwest Branch of the Anacostia River, 800 feet upstream from the crossing of Queens Chapel Road (Stop 1). Section measured by Leo J. Hickey and Norman Frederiksen, 1984. For key to symbols see Fig. 2.