58 Proceedings of the Royal Society of Victoria. 



The rocks referred to in this paper occur along the New South 

 Wales coast on the south side of the present outlet of the Shoal- 

 haven River at Crookhaven. They form a small headland on 

 which the Crookhaven lighthouse stands and also stretch a short 

 distance southwards, as a somewhat bi'oken line of low cliflFs. 

 Further south, the coast is low and stretches as a sandy beach 

 for some miles, beyond which, again, the higher cliffs in the 

 neighbourhood of Jervis Bay run out to sea. To the north of the 

 Shoalhaven entrance, another stretch of sandy beach extends in 

 the direction of Gerringong, where the well known fossiliferous tuff 

 beds of Black Head form an important feature of the coast line. 



The area under consideration is mapped as Perrao-Carbonifer- 

 ous, and the late C. S. Wilkinson^ in referring to this part of the 

 coast line says "At Wollongong, Kiama, and on both sides of 

 Jervis Bay, the marine beds of the Lower Coal Measures occur," 

 The rocks consist of more or less horizontally bedded dark 

 coloured argillaceous sandstones, but just to the south of the 

 Crookhaven headland, there is a slight arch with the axis running 

 out to sea, and a little to the north of this line, the marine 

 platform is cut into by a channel, about half a chain wide, 

 running more or less at right angles to the coast line and 

 evidently due to the more rapid weathering of a dyke. 



A small remnant of what appears to be portion of the igneous 

 rock in situ, protrudes through the sand in the centre of the 

 channel towards the shore end ; it consists of a fine grained 

 greenish grey rock. 



The shore shingle consists of a great variecy of rocks and an 

 examination of the marine platform shows it to contain rocks of 

 the same nature, embedded so firmly, that it was extremely diffi- 

 cult to extract them without injuring or breaking them. These 

 boulders are of all sizes, from small pebbles up to blocks a foot or 

 more in length ; many are smoothed, but sometimes only on one 

 or two sides, while in shape they are mostly irregular, often 

 somewhat triangular and elongate. Various kinds of igneous 

 and metamorphic rocks, such as porphyritic and granitic rocks, 

 schists and quartzites were observed, but time did not permit of 

 extensive collecting. A few likely boulders however were 

 extracted and fortunately several showed distinct polishing, with 



1 Notes on the Geologj- of New South Wales. C. S. Wilkinson, K.G.S., F.L.S., Depart- 

 ment of Mines, Sydney, 1882, p. 51. 



