THE VICTORIAN NATURALIST. 143 



minerals to be obtained from certain layers of the old lava flows. 

 Beyond general collecting of the above character, little or nothing 

 appears to have been done. 



Regarding the old volcanic rocks of the district, usually 

 referred to as " Older Basalt," Mr. Selwyn's original description 

 on his map gives a good idea of their character: — " Cliffs of hard, 

 dark basalt, with bands of soft red earthy porphyritic rock, 

 probably beds of volcanic mud. . . . " In his report * he 

 gives a much fuller and more accurate description of these rocks, 

 mentioning that — " The principal area occupied by them 

 extends eastward from Arthur's Seat to Cape Schanck, em- 

 bracing nearly the whole of the islands and southern shores of 

 Western Port Bay." Regarding the mapping of this area, ex- 

 ception has been taken to its delineation in the neighbourhood 

 of Sandy Point by Mr. T. S. Hall, M.A., in his report on the 

 geology of the Shoreham camp-out f for he remarks : — 

 " At Sandy Point, Mr. Grant tells me, Silurian crops out 

 on the beach pretty extensively. Selwyn maps the country 

 there as volcanic." On the 1854 map this area is undoubtedly 

 coloured wrongly, but who was responsible for this error it is 

 difficult to say. Apparently it should have been coloured as 

 Palseozoic, for the boundary, though perhaps a tentative one, is 

 clearly defined. The part towards Sandy Point is indicated with a 

 Tertiary capping. However, on the part apparently erroneously 

 coloured there is clearly printed a remark which also extends 

 well into the area coloured as Palsezoic : — "Very little rock to 

 be seen in place from which the geological formation can be 

 ascertained. Probably Palaeozoic sandstone and slate." This 

 would mean an extension of the Palaeozoic over towards and 

 under Sandy Point, as the Tertiary is mapped as yellow dots, 

 which is usually taken to indicate a thin capping. Then on the 

 1856 map, for some reason or other, the boundary line running 

 from Hann's station north-westerly is omitted, and the Palaeozoic 

 remark is contracted into the more northern areas. Thus, 

 though the later map has more detail, and covers a larger area, 

 the earlier one would have been better but for the slip in colour- 

 ing, so far, at any rate, as the Sandy Point area is concerned. 

 The 1856 map, however, shows the Tertiary outcrop on West 

 Head and its westerly extension, whereas this feature is absent on 

 the earlier one. This region, during the reign of volcanic 

 activity, must have been a particularly warm quarter, and it 

 appears to me that the whole series of volcanic rocks of this end 

 of the peninsula is but the remnant of a nest of volcanic cones. 



* " On the Geology, Palaeontology, and Mineralogy of the Country situated 

 between Melbourne, Western Port Bay, Cape Schanck, and Point Nepean, 

 accompanied by a Geological Map and Sections," by A. R. C. Selwyn. 

 November, 1854. 



t Vic. Nat., vol. xix., No. I, May, 1902, p. 17. 



