The excavations in Mound B revealed clearly its internal structure (Fig.
3). An old soil surface, unmistakably defined by a dark humic zone,
underlay the entire mound at an average elevation of 99 feet, or
approximately the same elevation as the modern surface of the
floodplain. This evidently represents the surface humic zone (Zone IIc)
of the floodplain at the time the mound was built. Yellow-brown sand
(Zone IIb) extended below the buried humic zone to an undetermined
depth. Zones IIb and IIc beneath the mound contained a few scattered
stone chips and an occasional artifact, but there were no concentrations
of cultural material.
[Illustration: Fig. 4
HARROUN SITE
41 UR 10
MOUND B AREA
contour interval = 0.5 feet
shading indicates excavated area]
Resting directly on the old floodplain surface was the basal structural
component of the mound, a rather compact, circular lens of dark brown
sand up to a foot or more thick and averaging about 17 feet in diameter.
This lens, which contained abundant charcoal, burned clay daub, bone,
shell, and a few artifacts, represented the floor level of a house,
designated House No. 3. In and above the floor level were the remains of
several charred poles, presumably derived from the burned framework of
the house. A burned area approximately four feet in diameter in the
center of the lens proved to be the remains of a central fire hearth. It
was filled with complex lenses of various shades and textures. A large
post mold was found beneath the hearth in the approximate center of the
house.
Completely encircling the house outline was a poorly defined zone of
yellow-brown sand which lay directly on the buried surface of the
floodplain and extended upward a foot or two where it gradually blended
into the upper component of the mound fill. This light-colored sand may
have been banked against the outside of the house while it was still
standing; or it may have resulted from uneven, subsurface staining by
charcoal and other organic material of that portion of the mound lying
directly above the house. In any event, it was virtually devoid of
cultural material, only a very few stone chips, widely scattered, being
found in it.
A well defined humic zone, resulting from organic staining after the
mound was built, appeared at the surface of the mound. It averaged about
0.5 feet in thickness.
Except for the clay in the hearth and in the house floor, the entire
mound was constructed of sandy soil like that of the surrounding
floodplain, whence it undoubtedly was derived. The depressions on the
northwest and southeast sides of the mound are probably the borrow
sources for the sandy soil. The clay could have easily been obtained
from exposures in the cut banks at the edge of the creek channel.