Regional geologic investigations show that all the metamorphosed crystalline rocks underlying the Greenville 1 degree x 2 degree quadrangle are allochthonous. Seismic-reflection studies, the COCORP line (Cook and others, 1979), and the U.S. Geological Survey (USGS) seismic lines (Harris and Bayer, 1979; Harris and others, 1981) present seismic profiles across different parts of the southern Appalachians. Recent geophysical studies for the now discontinued Appalachian Ultradeep Core Hole (ADCOH) project were concentrated in the Greenville quadrangle (Hatcher and others, 1988). The ADCOH seismic-reflection profiles tie in with the COCORP profile of Cook and others (1979), providing a three-dimensional view of the Earth's crust (Coruh and others, 1987; Hatcher and others, 1987, 1988). The seismic studies clearly corroborate the allochthonous nature of the crystalline rocks as suggested by geologic mapping. They also suggest that Paleozoic sedimentary rocks in several thrust sheets continue from the Valley and Ridge beneath the crystalline rocks of the Blue Ridge and under a part of the western Inner Piedmont. Harris and Bayer (1979) suggest 179 km of westward transport for the crystalline rocks of the Blue Ridge.