The surface and subsurface conditions of the survey site affect the
results of the two survey methods. The site which is located in a rural
area south Harrisburg, Illinois (Fig. 1) has a minimal cultural noise.
Denny et al. (2007) describes the regional geology of this area stating
that the site lies near the extreme southern edge of the Pleistocene
glaciation in Illinois. The unconsolidated sediments are mostly windblown
silt overlying laminated clay, sand, and silt, known as the
Equality Formation