52 



thrust consists of ground-up calcareous material in which it is 

 difficult to recognize distinct organic forms. 



The junction between the Eocene limestones and Cam- 

 brian slates is well shown at both the north and south ends 

 of the cliff section. At the north end (plate xii.) the base- 

 of the Eocene beds is marked by an irregular deposit, about 

 9 ft. in thickness, of earthy, calcareous, and carbonaceous 

 material, which may represent an ancient soil, or weathered 

 capping, antedating the marine deposits ; or, possibly, the 

 crushed-up material produced by a slide of the newer beds 

 over the old Cambrian floor on which they rest. The dis- 

 turbed area continues for a distance of about three-quarters 

 of a mile, and near its southern extremity a small creek has 

 exposed another cross-section of the unconformity between the 

 Cambrian and Eocene beds. Here the Cainozoic limestones 

 rest directly on the Cambrian slates. The latter are of a 

 bright-pink colour and exhibit parallel jointing to the plane 

 of imconformability which gives the misleading appearance of 

 an identity of dip between the Cambrian and Cainozoic series. 

 This effect is heightened by the bleaching that has taken place 

 along the joints of the Cambrian and thereby brought these 

 divisional planes into prominence. The dips of the respective 

 series, are, however, very distinct and discordant, the Cam- 

 brian beds dipping north 20° west at 85°, and the over- 

 lying Cainozoic limestones north-west at from 30° to 45°. 

 On the south side of this section the newer series forms a 

 capping on the Cambrian slates and rises from sea-level to< 

 the top of the cliffs parallel with the coast, where they run 

 out and are not again met with in a southerly direction 

 until Kangaroo Island is reached. 



The Cainozoic beds within the disturbed area have 

 suffered a greater or less degree of induration and make a 

 fairly hard and compact stone, but no other evidence of alter- 

 ation could be detected when examined either macroscopically 

 or microscopically. The general direction of dip varies from 

 west to north-west. 



Palceontological Notes. — Reference has already been 

 made to the polyzoanal composition of the limestones. In 

 this respect, as well as in the relative scarcity of molluscan 

 remains and the presence of echinoderms, the beds bear a 

 close resemblance to the upper beds of the same age in the 

 Aldinga cliffs. The large branching polyzoan, Cellepora, 

 which is common at Aldinga, is also abundant at Sellick's 

 Hill. The Turrit ella aldingcz beds which are at sea-level at 

 Blanche Point, Aldinga, are not seen in the Sellick's Hill 

 cliffs, although a few isolated examples of this form were 

 noticed in the polyzoanal rock. There can be no doubt that 



