Comprises interpretation of 62 line km survey shot by DME and 24 + 9 +km surveys shot by Geoseismic. Brief and very generalised description of geology is included. Continuous profiling (1/4 mile intervals) was employed with a weathered horizon correctional velocity of 7,000 f.p.s, and continuous reflections were obtained to approximately +6,900 feet (2-way time 1.52 secs). A linear increase of velocity with depth precluded generation at multiple reflections. A dip reversal +is present around SP 13 (at Grange). Closure depth is approximately +50 to 2,000, and 150' to 6,000'. Deep-seated faults occur at SP 25, +31, 53. A refraction of 5,000 f.p.s. represents shallow sediments, and another of approximately 18,000 f.p.s. at 2,300 - 2,600' represents inferred basal Tertiary. A third high speed layer occurs +either in basement (Proterozoic) or possibly limestone (Wilkatana). The deep section, which compares with the drifted Croydon Bore section, may be due to a major fault system approximately paralleling the inner side of the Rains Coastliner. Drilling of the Grange structural high is recommended.