This report deals with the stratigraphy and sedimentary history of the Chowilla area in the Murray Basin. Local geology is set against a background of geological information derived from other areas in southern Australia. Local stratigraphy is based on information from cliff sections and bores, including A.O.O. North Renmark No. 1 and the stratigraphic bore put down near the coat abutment of the Chowilla Dam site. Although the stratigraphic table shows the full sequence to Cambrian basement, emphasis is placed upon that portion of the Late Cainozoic sequence which extends from the Pata Limestone to the surface. According to Terzaghi, Karl (1955) the term “engineering properties of sediments” refers to petrographic factors, modes of transport and deposition, and changes after deposition. The most convenient method for the presentation of such information is a review of geological events, in this case of the sedimentary history of the area based on stratigraphic analysis. Because sedimentary history is so important, stratigraphy has been kept to a minimum in the text. The age, name, stratigraphic relationships and thickness of the beds, together with lithology, environment of deposition and distribution are set out on Table 1, which is to be read in conjunction with the text. To facilitate reference to the table, important rock units in the Chowilla area are named in the margin of the text. Photographs of cliff sections form the frontispiece. Important localities are shown on the locality map adjoining the frontispiece. Cliff sections in the Chowilla area are set out in Appendix A, and are identified by numbers which are also shown on the Chowilla and Renmark 1 mile geological maps. Bore logs are set out in appendix B in two groups: Group 1 contains bores used in a re-interpretation of geology along the dam axis, and group 2 contains bores shown on the Chowilla and Renmark 1 mile geological maps. An air photo showing location of the dam axis, the geological section along the dam axis and the stratigraphic table are included.