A section was measured across the Umberatana Group - Wilpena Group boundary near Wilmington in the Southern Flinders Ranges, on the western margin of the Adelaide Geosyncline. Grey red massive siltstones are correlated with the Reynella Siltstone Member and the Elatina Formatio. No evidence for glaciation was observed. The overlying Nuccaleena Formation is composed of several metres of pink, thinly bedded dolomite. In the Buckaringa-Warren Gorge area where a similar sequence has been described, the contact between the Elatina and Nuccaleena Formation is sharp (Jablonski, 1975). Twenty six metres of interbedded sandstones and siltstones in the lowermost Brachina Formation, dissimilar to those underlying the Nuccaleena Formation, are equated with the Seacliff Sandstone Member. A bed 30m above the Nuccaleena Formation, contains a (35 x 10) cm very angular block of 'bluish-grey' laminated siltstone embedded in sandstone. It may be a piece of Tapley Hill Formation. The base of the Seacliff Sandstone Member in the type section can be taken as the base of the Wilpena Group, whilst the Nuccaleena Formation is taken as the base in the Flinders Ranges. The relationships of the Nuccaleena Formation and Seacliff Sandstone Member is one of complex intertonguing.