In September of 1984, the USGS and the Canadian Department of Energy, Mines, and Resources conducted a seismic-refraction experiment in Quebec and Maine. This experiment - part of a large interdisciplinary effort to understand the structure ond tectonic evolution of the northern appalachian orogen - was designed to sample several different tectono-stratigraphic terranes which have been indentified in the northern Appalachians. A 300-km-long profile crossed the land exposure of the Appalachian orogen perpendicular to strike and parallel to seismic reflection profiles also recorded in Maine and Quebec. Full size version of plates available in additional file with the report.