A site investigation has been carried out for G. Maunsell and Partners, Melbourne, for the proposed new Morphett Street and Victoria Bridges, in the City of Adelaide. The investigation was requested in a letter to the Director of Mines dated 21st February 1964. The proposed bridge sites are in Railway Reserve, Hundred of Adelaide, and extend north across the Torrens Lake to the North Parklands, Hundred of Yatala. The Morphett Street Bridge will be a series of spans similar in length to those of the existing bridge. The new Victoria Bridge is proposed as a single span approximately 250 feet in length. Width of carriageway on both bridges will exceed 70 feet, more than twice that of the existing structures. Torrens Lake at the site of the new bridge will be widened by some 30 feet. Drilling commenced on the 5th May, 1964, and was completed on the 3rd September 1964. The investigation consisted of 16 percussion drillholes with a total depth of 1140 feet. The holes were open tube sampled throughout, and undisturbed sealed tube samples were recovered and 26 were forwarded to the Civil Engineering Laboratory, University of Adelaide, for testing. Standard Penetration Tests were made in all but two drillholes, at depths decided upon after consideration of the geological succession. Tests in Holes 1,2,4,5,11 and 12 were made by equipment which proved unsatisfactory, and the results of these should be disregarded. All other Standard Penetration Tests were made using satisfactory equipment and the results are considered to be reliable. Pocket Penetrometer readings of unconfined compressive strength were carried out during logging, and the results are shown on the drill hole logs. The holes were logged on a scale of 1 inch = 10 feet. The logs show the geological succession encountered in the hole, and in addition the materials sampled have been classified according to the Unified Soils Classification System of the U.S. Bureau of Reclamation. Palaeontological examination of the materials was undertaken by the Palaeontological Section, South Australian Department of Mines.