Figure 5 . Arbitrary Unit 1, East-West profile at N1002 line, looking north. Layers: 1a, plow zone, a mix of black organic silty loam, humus, and underlying clay with sand; 1b, black silty loam with humus, mainly filling soil cracks; 3a, yellowish-brown to yellowish-gray clay with abundant quartz sand inclusions; 4, Light gray silty loam with quartz sand and pea gravel, and tabular metamorphic stone pieces (laying horizontally).