Seismic velocity discontinuities in the bedrock refractor at the site of an amphibolite deposit near Tailem Bend have been used to outline the contact of the amphibolite with the surrounding schist. A high velocity (1500 m/s) calcrete layer, where it is present, precludes accurate depth estimation, as it forms a velocity inversion layer in the low velocity (500 to 400 m/s) clays and sands which form the overburden. The schist has a velocity range of 2400 to 3400 m/s, while the amphibolite has velocities in the range 4500 to 6000 m/s.