On 30th March 1960 a seismic velocity survey of the A.A.O. Timbury Hills No.2 bore near Roma, Queensland, was made as a joint investigation by the Bureau of Mineral Resources and Associated Australian Oilfields N.L. The bore is located about two miles north east of Roma (Plate 1) and had been drilled to a depth of 4400 ft. The formations drilled were mainly sandstone and shale of Mesozoic Age to a depth of 3845 ft, where a much harder and denser formation was encountered. This formation is called (by A.A.0.)-the Timbury Hills Formation and marks the base of the Mesozoic sediments at this location in the Great Artesian Basin. No age has yet been assigned to the Timbury Hills Formation. Detailed lithological and electric logs of the bore were made available by A.A.O. to aid in the interpretation of the velocity survey.