The relationship between 2-D and 3-D wave propagation in horizontally layered media was first investigated by Dampney (1971). In the last few years the usefulness and feasibility of transforming point‐source responses with 3-D geometric spreading to equivalent line‐source responses with 2-D geometric spreading have been thoroughly discussed (see Helgesen, 1990; Wapenaar et al., 1990, 1992; Herrmann, 1992; Helgesen and Kolb, 1993; Amundsen, 1993). In the case of cylindrical symmetry this transformation constitutes a required preprocessing step for several seismic processing algorithms based on 2-D wave propagation. The work of Dampney (1971) has apparently been missed by the authors discussing the 3-D to 2-D geometric spreading transform.