158 THE VICTORIAN NATURALIST. 



a grey colour, sometimes nearly black, and contain frequently 

 traces of carbonaceous matter, which at Mentone form thin 

 seams ; with these are patches of a pale yellow mineral, probably 

 basic sulphate of iron. Near Mentone these lower beds at one 

 place pass into a ferruginous sandstone. At various places on 

 the coast between Beaumaris and Sandringham a similar rock 

 occurs to a small extent, and at Red Bluff again we have distinct 

 patches of carbonaceous matter. These pass gradually at 

 Mentone into a friable sand rock, formed of coarse quartz sand 

 and more or less iron oxide, and varying in colour from white to 

 yellow and red. Similar rocks occur throughout the district, and 

 form the main part of the lower sand ; but only at Mentone does 

 the complete series appear without a break. In other places 

 there is a break between this and the underlying portion of this 

 series, or the lower portions are entirely absent. The lower 

 portions of the sand frequently are finer and more compact, with 

 ironstone bands, and at Windsor and St. Kilda beach contain 

 thin beds of ferruginous sandstone, resting on the Silurian rocks. 

 The greater part of this deposit consists of coarse sand, with a 

 few rounded quartz pebbles, and varies greatly in colour and con- 

 sistency. Its colour is white, yellow, or any shade of brown or 

 red, according to the quantity of iron oxides present. Sometimes 

 it is very friable, sometimes hard and compact ; and this harden- 

 ing may take place along certain beds or in irregular bands and 

 patches. The present surface is very irregular and usually covered 

 by gravel, which seems to have been formed by the removal of 

 the finer and softer parts of the rock. The gravel varies in 

 amount and nature according to the variations in the underlying 

 rocks. At some places, as in the cutting south-east of Elstern- 

 wick station, a large mass of sandstone is left on the top of the 

 sand, projecting into the newer deposits, being a hard por- 

 tion of a higher bed which has resisted breaking up and has 

 been too heavy to remove. The sand sometimes contains a large 

 amount of clay, and at one place, between Brighton Beach and 

 Picnic Point, it is very calcareous ; but this calcareous rock passes 

 gradually into the ordinary sands. The lime percolating through 

 has here filled all the cracks in the underlying rocks forming 

 vertical and horizontal sheets and irregular patches of impure 

 crystalline limestone among them. 



After the erosion of these deposits to near their present form 

 there followed another series of deposits, the upper sand, referred 

 to before, associated with which are two shell beds. The lower 

 of these, which I have seen only at Picnic Point, contains all 

 recent species, though some are not found or are rare there now. 

 It, at first sight, appears to run into the lower sand ; but further 

 examination shows that this is not the case. It is a few feet 

 above the present water level at its highest part, and descends to 



