Art. XIV. — On some Rocks from, the fairivay of Port 

 PJiillip Heads. 



By R E. grant and E. O. THIELE. 



[Eead 9th October, 1902.] 



Blasting operations were recently carried on at Port Phillip 

 Heads under the supervision of the Engineer for Ports and 

 Harbours with the view of deepening the Channel, so as to 

 render the passage safer for ocean going vessels, and by this 

 operation large blocks of stone were obtained containing 

 numerous embedded fossils. 



A block of this stone was obtained by the writers, and was 

 found to consist of coarse sandy limestone of a creamy colour, 

 composed mainly of a mixture of quartz grains and comminuted 

 shell remains. On the side of the fresh fracture it was less 

 compact and showed indistinct lines of stratification. This part 

 of the rock was full of shell remains, all, unfortunately, more or 

 less broken and corroded. By far the commonest form was a 

 Bankivia sp., but on close examination we were able to identify 

 the following : — 



Bankivia sp. (aff. varians). 



Mesodesma elongata. 



Chione striatissima. 



Mytilicardia aviculina, 



Corbula sp. 



Tellina sp. 



Glycimeris sp. 



Echini spines. 

 A sample of the rock treated with acid was found to consist of 

 a little over 50 per cent, of carbonate of lime, the insoluble 

 residue being grains of quartz — angular for the most part, with 

 occasional more or less rounded fragments intermixed. 



The chart shows that a rocky platform or reef extends from 

 Point Nepean to Point Lonsdale at a depth along that line of 



