Continuous magnetic profiles were recorded by a truck-mounted magnetometer along road traverses over stratified metamorphic rocks and plutonic igneous rocks of the New England Appalachians. The records show a series of distinctive, highly detailed magnetic anomalies which closely reflect the nature and distribution of near-surface bedrock units. The method provides a rapid and versatile means of discriminating bedrock units, which should be especially useful in regions where bedrock exposures are scarce. Under some conditions, analysis of the anomalies may yield critical data on the shape and magnetization of individual rock units. These data should prove useful for deducing geologic structure and for general studies of the magnetization of rocks.