INTRODUCTION TO THE GUIDE As superb exposures of fossiliferous strata, refreshed by coastal erosion and winter storms and backing popular beaches in what is now suburban Adelaide, the coastal cliff sections in the Willunga Embayment have attracted the attention of naturalists and painters since the mid-19th century. For the stratigraphy and micropalaeontology that solved Adelaide’s problems of foundations and water supplies, they have been the key reference point. In the broader scene they offer something to two geohistorical enquiries, namely the birth of the Southern Ocean in the death of the Australo-Antarctic Gulf, and the impact of that development on the greenhouse-to-icehouse global transformation. The Saint Vincent Basin is approximately 15 000 square km in area, about 60% of which lies beneath Gulf St Vincent. Together with the Mount Lofty Ranges, it originated in compressive reactivation of ancient structures in the Middle Eocene, just as Australian-Antarctic separation accelerated. A series of arcuate faults broadly following the grain of Delamerian (early Palaeozoic) structures define sub-basins or embayments — wedge-shaped asymmetrical tectonic valleys: the Willunga Embayment, Noarlunga Embayment, and Golden Grove Embayment. The basin straddles the south end of the Torrens Hinge Zone, which lies between the Flinders-Mount Lofty Ranges and the Stuart-Spencer Shelf to the west. This zone is the ‘Great Valley’ of J.W. Gregory in 1906 and the ‘South Australian Rift Valley’ of Charles Fenner in 1927, with its sunklands, corridors and horsts. For essentially the same tectonic reasons, the Cenozoic basin has been denied full oceanic influence from the widening Southern Ocean owing to the position of Kangaroo Island. The modern account of the Cenozoic record begins with Glaessner’s marine micropalaeontology and stratigraphy in the 1950s (Glaessner, 1951, 1953; Reynolds, 1953; Glaessner and Wade, 1958; Wade, 1964), and continues with Lindsay’s (Lindsay, 1967; Ludbrook and Lindsay, 1969). The two decades 1950-1970 are outlined in McGowran (2012). Meanwhile, Campana and Wilson (1953) and Sprigg and Wilson (1954) produced the Geological Survey one-mile sheets. Ward (1966; 1986) described and ambitiously synthesised the geology, geomorphology and soils of the district. Cooper (1977, 1979) monographed the stratigraphy of the Willunga Embayment. Modern lithostratigraphy and mapping are to be found in Fairburn (1998, 2000) and Fairburn, Preiss, Olliver and White (2010). Jones and Fitzgerald (1984, 1986, 1987) discussed the mineralogy and significance of the unusual Priabonian silicas; James and Bone (2000, 2008) described the Palaeogene carbonates and silicas. A geological excursion to the Willunga Embayment is a flexible mixture of three components. The best known is walking the coastal traverse up-section, north to south, from Maslin Bay to Blanche Point and from Perkana Point to Aldinga Bay. A second uses vehicles from outcrop to outcrop and winery to winery and neatly brackets the embayment with the great unconformity in the north and the best view of the Willunga Fault in the south. Third is a walk to the far south beyond Sellicks Beach, to coastal outcrops and gullies exposing the neotectonic record but requiring attention to tide times.