144 THE VICTORIAN NATURALIST. 



Judging by the decomposed breccia beds, ash beds, lava streaks, 

 and occasional dykes, by the changing dip of the ash, and other 

 layers at diflferent spots, there were several points of eruption in 

 the neighbourhood. One of these I would locate near Shoreham, 

 and inland from the present coast ; another about a mile and a 

 half west from West Head and close to the present coast line ; 

 and a third a short distance seawards from Elephant Rock and 

 the Blowhole, a locality about three miles east from Cape 

 Schanck. The Cape Schanck material may have come from the 

 same point of eruption as the last, or perhaps from a closely 

 adjoining vent. 



Sehvyn remarks on the hardness of the olivine basalt and on 

 the absence of scoriaceous trap. Certainly some of the rock is very 

 dense, especially some of the shingle pebbles, but a great deal of 

 it is vesicular to a considerable extent, apart from some of the 

 zeolite layers, which are particularly cavernous. The materials 

 appear to me to clearly indicate the eruption of alternations of 

 ash and lava, some of the ash being fairly coarse, angular 

 fragments, apparently of decomposed scoria, of considerable 

 dimensions being frequently met with at each of the above- 

 mentioned localities. In some of the coast sections as many as 

 eight and nine lava flows with intercalated layers of ash and 

 breccia can be distinctly made out, especially at the Elephant 

 Rock section. 



The basalt layers are well and closely jointed, and as a 

 consequence the weathering has made marked inroads, and much 

 of the rock is badly decomposed. Very good examples of 

 columnar and tabular jointing may be examined at various spots, 

 the latter structure being on the fine as well as on the coarse 

 scale. On the other hand, the ash layers, owing to their present 

 clayey consistency, are tough and tenacious when wet, and resist 

 removal to a marked extent, but when dry shrinkage cracks break 

 the mass up in a more or less rubbly manner, and the material 

 falls away rapidly. Thus, in the cliff sections above high water 

 mark the ash layers are frequently somewhat excavated, whilst 

 the harder basalt layers, though much battered-looking and 

 rounded off, form fantastic projections which lend to the cliffs 

 along this coast much of their natural beauty. 



Then, again, the marine denudation lends another and perhaps 

 the strongest charm. The ceaseless battering to which the base of 

 the cliffs is subjected appeals to one so strongly that more result 

 is almost expected, for when one visits the same spot year after 

 year, and can notice no appreciable difference, the enormity of 

 time required by Nature for most of her carvings appears quite 

 incomprehensible. Yet there is the result. We gaze ! and admire ! 

 and try to comprehend as much as possible. 



[An excellent series of lantern views was shown in illustration 

 of the author's remarks. — Ed. Vict. Nat.] 



