The geology at the Harroun Site may be summarized in tabular form as
follows:
Zone II. A stratum of sand forming the surface of the floodplain,
varying from about 5 to 12 feet thick. Zone II was divided into three
parts, IIa, IIb, and IIc.
Zone IIc. Humus-stained topsoil, the superficial portion of the Zone
II sand member, 0.6 to 1.1 feet thick.
Zone IIb. Grayish to whitish sand with irregular-shaped patches of
brownish sand. The brown patches probably represent subsurface
staining of the gray-white sands by iron salts carried by percolating
water. Zone IIb was 2.0 to 3.1 feet thick where exposed.
Zone IIa. Grayish to whitish sand similar to IIb, but without the
patches of brown sand. This zone was heavily saturated with subsurface
water wherever encountered, and the presence of the water may have
kept the iron salts in solution, thereby explaining the absence of the
stains. The thickness of Zone IIa was not determined since seeping
ground water prevented excavating down to its base.
Zone I. A reddish clay member observed in natural exposures along the
edge of the creek channel. The top of Zone I was undulating, and it
lay at a depth of approximately 5 to 12 feet below the surface of the
floodplain in the exposures examined. The thickness was not
determined, but was in excess of 10 feet. The top of Zone I was not
reached in any of the excavated squares because seeping ground water
prevented carrying the excavations deeper than 4 to 5 feet.