304 



sandy bed, which passes, in places, into a rock consisting ahiiost entirely of 

 broken polyzoal remains. Fossils are fairly common in the bed, but have a 

 limited range as to species ; thickness of bed, 30 feet. The face of the clifif is 

 almost vertical. In the lower part, the upper members of the Miocene Series 

 are exposed, the harder layers standing out in relief, as shown in the photograph ; 

 and, near the top of the clifif, the Lower Pliocene limestone, underlain by a 

 reddish sandstone that carries most of the fossils of these beds, can be seen 

 (see also Tate, R., 1896, p. 123). 



The headland of Blanche Point forms the northern limits of Aldinga Bay. 

 From this point the clififs make a slight landward curve and lose their precipitous 

 character. Between the headland and Aldinga Creek (about a mile) 

 the cliffs are in three stages. The lowest scarp is formed by Recent clays and 

 blown sand, which make a hummocky slope lying against the Tertiary beds and, 

 for the most part, obscuring the outcrops of the latter. The second scarp is 

 formed by the white limestone of the Lower Pliocene beds, which, being resistent 

 to weathering, makes not only a scarp face, but a well-defined platform, or shelf. 

 On this shelf — set back from the edge — ^the older and newer fluviatile beds 

 form a third scarp. 



The Aldinga Creek, which reaches the sea near the township of Port Wil- 

 lunga, breaches the cliffs and interrupts the continuity of the section. The cliff? 

 that rise on the northern side of the creek exhibit some interesting features. A 

 highly coloured bed of sandy clay, in red and yellow layers, forms a conspicuous 

 feature in the cliff face, near the base. No fossils could be detected in this 

 bed, which has the appearance of being a freshwater deposit. It is from 4 feet 

 to 5 feet in thickness, and is seen to rest conformably on a dark-coloured clay 

 that is sparingly fossiliferous near the plane of junction. One or two examples 

 of Limopsis insolita and Turritella aldingae were observed here ; but at a lower 

 level, in the same bed, situated on the tidal slope, remains of Turritella are 

 abundant. 



Resting on the highly-coloured clay bed is a yellowish limestone consisting 

 almost exclusively of small polyzoal remains. It is false-bedded and fissile, and 

 is overlain by the Lower Pliocene sands and limestones. This section proves 

 that the reddish (?) freshwater bed is included in the Miocene Series. The 

 jbeds here have a dip of from 3° to 4° in a south-westward direction. This 

 inclination causes the red-coloured bed to dip below the surface to the south- 

 ward, but takes a rise to the northward. 



At about a quarter of a mile to the northward of Aldinga Creek — on the 

 northern side of the Memorial Life Buoy erected on the beach — the red clay bed 

 makes a small waterfall in a washout, and is underlain and overlain by beds 

 as they occur at Aldinga Creek (described above). No continuous section of the 

 Miocene beds can be traced from this point, for nearly a mile, being much 

 obscured by Recent clays. The red clay bed (interstratified with the fossiliferous 

 Miocene), of supposed freshwater origin, is seen at intervals for some distance 

 beyond the washout, mentioned above, but appears to thin out to the northward. 



At Port Willunga jetty the older marine beds are represented by more or 

 less consolidated sands that are exposed in a thickness of about 20 feet and are 

 moderately fossiliferous. On account of the open texture of the rock the 

 organic remains are limited to such forms as are the more stable in relation to 

 the circulating waters that cause solution, such as Pecten, Magellania and other 

 brachiopods, polyzoa, echinoderms, etc. It is difficult to say whether this 

 lithological change in the sediments is due to local variation simply, or whether 

 these sandy deposits occupy a stratigraphical position superior to those exposed 

 at Blanche Point, but were removed from the latter by denudation before the 

 laying down of the newer marine deposits which cover all alike. A break in the 

 cliff section leaves this an open question. 



