Between February 1996 and November 2000, geophysical logging was conducted in 27 open borehole wells in and adjacent to the Butz Landfill Superfund Site, Jackson Township, Monroe County, Pa., to determine casing depth and depths of water-producing zones, water-receiving zones, and zones of vertical borehole flow. The wells range in depth from 57 to 319 feet below land surface. The geophysical logging determined the placement of well screens and packers, which allow monitoring and sampling of water-bearing zones in the fractured bedrock so that the horizontal and vertical distribution of contaminated ground water migrating from known sources could be determined. Geophysical logging included collection of caliper, natural-gamma, single-point-resistance, fluid-resistivity, fluid-temperature, and video logs. Caliper and video logs were used to locate fractures, joints, and weathered zones. Inflections on single-point-resistance, fluid-temperature, and fluid-resistivity logs indicated possible water-bearing fractures, and heatpulse-flowmeter measurements verified these locations. Natural-gamma logs provided information on stratigraphy.