50 



by a short space of Cambrian slates which take the place of 

 the Cainozoic limestones in the cliffs and on the beach. 



The northern section forms low cliffs up to 15 ft. in 

 height, or, where small washouts have cut back into the 

 alluvial beds that overlie the limestone, the latter is exposed 

 up to 20 ft. in height. The rock is easily operated upon by 

 the waves, and as the cliffs come within the range of high 

 tides, the limestone, throughout its entire length, exhibits a 

 series of caves by the undermining of the sea. The beds are- 

 not quite horizontal but roll in long, low curves, with an. 

 extreme inclination not exceeding 15 c , on the one side pitch- 

 ing to the south-east, and on the other, to the north-west. 



In addition to its occurrence in the cliffs, the Eocene- 

 limestone occurs on the beach, between tides, and, apparently, 

 below low water, in the form of an extended floor or tabular 

 reef. The limestone cliffs disajDpear shortly before reaching 

 the outlet of Boundary Creek, but the flat reef of the littoral 

 zone continues to the southward until nearly opposite the 

 Waterfall Creek (No. 1), situated at the north side of Section 

 278 (Hundred of Myponga), and about one-third of a mile 

 south of the Boundary Creek. The position of this creek has 

 been carefully defined for the reason, that, within its chan- 

 nel, not far from its outlet, there occurs a limited outcrop* 

 of the Eocene limestone which is of some interest. It is here 

 that the first evidence of an unusual dip in the Cainozoic 

 rocks is markedly evident, as the limestone has a dip north 

 20° west at 48°. The outcrop is in the form of a bar, which- 

 crosses the creek, but is obscured on either side by a cover 

 of alluvial wash of great thickness. Its position, with respect 

 to the Cambrian slates, is peculiar, as it lies almost at the base 

 of a great scarp of these rocks which show a vertical height of 

 150 ft. facing the sea. The waterfall (No. 1) occupies an 

 acute niche in this scarp-face, and then there is a sheer drop- 

 of 20 ft., as the water falls over the edge. The Eocene lime- 

 stone in this peculiar position is probably a truncated frag- 

 ment from what was once a considerable sheet of these rocks, 

 resting at a high angle on the down-throw face of the Cam- 

 brian beds, as is still the case with the limestones a little further 

 south, but the encroachments of the sea have cut away the 

 upper portions of the fold, leaving a floor of the limestone 

 at sea-level in the fragment referred to. 



Immediately to the south of the creek, just described, 

 the Eocene limestones have been completely removed by 

 marine erosion for a distance of about a quarter of a mile, 

 and in this interval the cliffs consist entirely of Cambrian 

 slates, of buff and purple colours. Within this section of the 

 cliffs there occurs another small waterfall (No. 2), fed by 



