STRUCTURE OF MOUND C
Profiles of Mound C revealed remnants of an old stabilized surface with a well developed soil profile (including a superficial humic zone) lying immediately beneath the mound fill ([Fig. 7]). The elevation of the old surface averaged approximately 99.4 feet which is also the average elevation of the modern floodplain surface around the mound: therefore it appears certain that the first of the two houses was built directly on the floodplain surface and that there has been no appreciable change in the surface elevation of the floodplain since the mound was built. The first house burned, after which the second house was built over its remains; then the second house burned and the mound was erected over the ruins of the houses.
Fig. 7
HARROUN SITE
41 UR 10
PROFILE OF MOUND C
(IDEALIZED SECTION THROUGH CENTER OF MOUND)
pothole
floor of House No. 2
floor of House No. 1
sterile zone between house floors
post mold
humus (note buried humus zone between N130 and N140)
gray, sandy mound fill
whitish, sandy mound fill
undisturbed sub-mound soil
HARROUN SITE
41 UR 10
PROFILE OF MOUND D
(IDEALIZED SECTION THROUGH CENTER OF MOUND)
pothole
floor of House No. 4
dark brown sand
gray-brown sand
post mold
humus
gray, sandy mound fill
whitish, sandy mound fill
undisturbed sub-mound soil
A low embankment of sand similar to that at Mound B encircled the house area just outside the peripheral ring of house post molds ([Fig. 7]). Apparently this embankment was built while one of the houses was still standing since its inner edge is almost vertical in places as though it had been banked against the outside wall of the house. After the later house burned, the mound was heaped over both this embankment and the house ruins.
The geologic structure of the floodplain at Mound C was apparently the same as previously described although none of the excavations were carried deep enough to expose Zone I, the basal member of reddish clay. The mound structure rested on the surface of Zone IIc ([Fig. 7]) and was composed of four distinct structural units as follows (in order from bottom to top):
1. The lower house floor zone (House No. 1). This zone was composed of blackish sand containing a large amount of charcoal and had an average thickness of about 0.3 feet. It yielded some artifacts. This lower house floor lay just above the surface of Zone IIc (the floodplain surface) from which it was separated by a thin (approximately 0.1-foot thick) lens of compact sandy clay. The thin clay lens was apparently a subsurface formation resulting from the deposition of clay by percolating water along the buried surface of the floodplain.
2. The upper house floor (House No. 2). This zone consisted of a slightly compacted, brownish sand containing a large amount of charcoal and a few artifacts. It lay above the floor of House No. 1, and was separated from it by a layer of clean, sterile, yellowish sand 0.1 to 0.3 feet thick which probably was placed over the burned ruins of the first house to provide a clean floor for the second one.
3. The embankment of yellow-brown sand encircling the house area. As was previously pointed out, this member had the appearance of having been banked against the exterior wall of the house while it was still standing. Perhaps this provided extra protection from the winter winds, or its primary purpose may have been to serve as a dike to protect the house when Cypress Creek overflowed its banks. The maximum height of this zone was 2.0 feet above the surface of Zone IIc, upon which it rested.
4. The final addition to the mound. This was the sand member which had been mounded over the house ruins. It was virtually sterile of cultural material.