Sounding curves which are non linear show high and low values because of the variations in conductivity of the soil strata. Sounding curve rises when resistivity increases and falls when resistivity decreases at half current electrode separations. Depending on the maximum current eleclectrode separation , which determines the depth penetrated, a rise and fall signature of sounding curve is continuous. The curve will break or stop at the end of the hall current electrode separations. In as much as the current flows within argillites or arenaceous materials, the curve cannot break till it gets to the end of the maximum half current electrode separations.