55 



Mactra Hamiltonensis M. polita, Chem. 



Solen sordiclus S. Sloanii, Gray 



Barnea tiara B. australasise, Gray 



Terebra subspectabilis T, spectabilis, Hinds 



additoides T. ustulata, Deshayes 



Crepidula sp. C. unguis, Lam. 



Planaxis sp. P. mollis, Sow. 



It will be necessary here, for the sake of comparison, to refer 

 briefly to some of the other marine tertiary deposits of Victoria. 



On the shores of Port Phillip Bay, outcrops of such strata 

 occur, amongst other places, at Morning-ton, between Mount Eliza 

 and Mount Martha, and at Mordialloc, and fossils from both 

 localities have been described by Professor McCoy in the Prodro- 

 mus of Victorian Palaeontology. As far as can be judged from 

 the comparatively small number of species yet recorded, the de- 

 posits of Morning*ton are represented in the lower, and those of 

 Mordialloc in the upper Muddy Creek beds. 



At Portland Bay, and also on the Glenelg River, two sets of 

 strata are exposed, viz., a lower one composed of friable lime- 

 stone, in which brachiopods, echinodermata, and foraminifera are 

 the prevailing fossils, and an upper one consisting almost entirely 

 of oyster shells. Concerning the age of the former of these there 

 is considerable difference of opinion amongst geologists, some con- 

 tending that it is older than the Muddy Creek beds, while others 

 regard it as younger. 



The upper deposit, or ostrea limestone, has been noticed as a sur- 

 face formation at various places, not only near the coast, but also 

 for some distance inland, and it must at one time have ex- 

 tended over a wide area. The most interesting outcrop of it 

 known to me is at the Whaler's Bluff, Portland, where its junc- 

 tion with the older formation is clearly seen. Bising from the 

 water's edge, the latter, easily recognisable by the fossils it con- 

 tains, reaches about 40 feet up the cliff, when the ostrea limestone 

 appears resting upon it. This extends for the next 12 or 15 feet, 

 and is there overlain by igneous rocks, which continue up to the 

 summit of the cliff, a height of about 100 feet. 



While exploring here a few months- ago, I made the curious 

 discovery that the two sets of strata are actually separated by a 

 pebble band of a few inches in thickness, horizontally disposed, 

 and distinctly traceable, not only on this cliff, but also on an ad- 

 joining one. The pebbles vary in size from a diameter of about 

 one and a half inches to that of a few lines only. They are of a 

 light-brown colour, and very irregular in shape, some being nearly 

 circular, some flattened, and some elongated; the edges of all are, 

 however, more or less rounded, from which it may be concluded 

 that they are rolled fragments, just as the nodules at Muddy 



