GEOLOGICAL CONTEXT
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 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.
Excavation and Recording Methods
The same general procedure was followed in excavating each of the four mounds at the Harroun Site. A stake was placed near the center of the mound and a grid of 5-foot squares was established which tied in with the centrally located stake. Then each quadrant of the mound was excavated separately. Beginning at the top of the mound, an entire quadrant was taken down by regular vertical intervals, usually of 0.5 feet each. The floor of the excavation was cleaned and examined after each level was removed, and measured drawings were prepared to record any zoning or occupational features that were observed in the excavation floor.
The four profiles radiating in the cardinal directions from the central stake were always left intact until measured drawings had been prepared, and other profiles were recorded when deemed necessary. Strategically located check blocks were left at all the mounds, at least until the structure of the mound was determined. In some cases the check blocks were ultimately removed in order to completely expose a house floor or other feature.
For vertical reference, the base stake at Mound A was assigned an arbitrary elevation of 100.0 feet, and all vertical measurements for the entire site were keyed to that stake. For horizontal control a separate grid of 5-foot squares was established for each mound and the area adjacent to it. While the use of a separate grid for each mound had some disadvantages, this method was adopted for two main reasons: (1) so that a key stake with co-ordinates in whole numbers could be located at the center of each mound, and (2) to avoid the use of unwieldy 4-digit numbers for co-ordinates. For each grid a base stake, set well away from the mound, was assigned an arbitrary designation of 0-0, and all other stakes of that grid were labeled with the co-ordinates measured from the base stake in the cardinal directions (as N100-W50, N85-W80, etc.). All the grids were oriented on magnetic north. The designation for each 5-foot square was taken from the co-ordinates at its southeast corner.
Because of the press of time it was impossible to screen all of the excavated soil. Each structural component was spot screened, however, in order to obtain a representative sample of artifacts and other material. Both ⅓-inch and ¼-inch hardware cloth were used for screens.