COLONIAL GEOLOGY — MELBOURNE. 



31 



confined to particular organisms, but is due probably to the same causes 

 as are the colours of the fossils in the Botanical Garden quarries. 



Moonee Ponds is, and perhaps will long remain, the most plentifully 

 stocked preserve for the Melbourne collector. The prevailing rocks are 

 shales and sandstones, the latter, in many places, being literally made up 

 of marine exuvia, matted together, organism upon organism, in such a 

 manner as to render the extraction of a perfect fossil a matter of some 

 little difficulty. 



The general custom of these beds as depicted on both maps, but more 

 especially that which shows the surrounding country on a smaller scale, 

 present an outline peculiarly suggestive. It will be observed that the 

 borders of the formation are turned principally towards south and westerly 

 points of the compass, the eastern boundary abutting against the granitic 

 and porphyritic masses of the Dandenong ranges. Seen alone, as there 

 represented, the above fact might be deemed hardly worthy of remark ; 

 but the bold cliff-like escarpments which form the outline in many places, 

 such escarpments having almost invariably a south or westerly aspect, 

 suggests the cause, and tells of strong currents, oceanic action, and a steep 

 and rocky shore exposed to the full fury of an extensive and stormy waste 

 of water. Near Melbourne, in Studley Park, overlooking the flats of Rich- 

 mond and Collingwood, the feature alluded to is strikingly apparent. 

 Standing on the lower ground, the resemblance to a precipitous coast is 

 especially manifest ; whilst gazing from the summit, one is almost inclined 

 to fancy the many undulations of the ground below are the arrested bil- 

 lows of some ancient sea. At times, as a thick fog covers the plain be- 

 neath, and when the higher portions of city and suburb just peep out of 

 the mist-like islets, the old and fancied state of things seems realized ; 

 whilst from the Tertiary beds below and their wide extension, almost uni- 

 versal in a south-westernly direction," save in the case of a few granitic 

 masses, Mount Eliza, Mount Martha, Arthur's Seat, and the Yowangs, 

 the student well knows that the time could not be geologically far distant 

 when the waves, breaking near the spot whereon he stands, came rolling in 

 from an expanse of ocean uninterrupted by land, rock, or island, nearer 

 than the Falklands or the Horn. 



Tertiary deposits are developed to a great extent over the whole of 

 Australia, and are well represented in the Melbourne district ; more so, 

 in fact, than appears upon the map, since they both overlie and underlie 

 the basaltic lavas, and besides cover with a thin capping in many places 

 the upturned edges of the elder Silurian strata. 



A tolerably good view of the Upper Tertiary beds can be obtained by 

 following the line of the Melbourne and Brighton railway, along which, 

 after the first few miles, where Basalt and outlying patches of Silurian 

 rocks are traversed, some thick beds of the newer Pliocene are exposed. 

 In a cutting near Chapel Street station, three or four miles south-west of 

 Melbourne, a junction of the older with the newer rocks discloses a somewhat 

 instructive section. The Silurian beds had there formed an abrupt coast- 

 line, or at least an uneven and rocky bottom, and upon them rests in un- 

 conformable stratification the Tertiary sediment above, — forming a number 

 of thin beds, gradually growing less and less curved, until attaining 3 or 4 

 feet in thickness, when all traces of the uneven bottom is lost by the suc- 

 ceeding deposits being thrown down in nearly level lines. 



From this point on the line the same Tertiary beds are exposed in each 

 succeeding cutting as far as Brighton, a suburban watering-place eight miles 

 from the metropolis, on the shores of Port Phillip Bay. On the beach neal 

 Brighton, small outcrops of Lower and ferruginous Pliocene beds first 

 present themselves, and, pursuing the line of coast, these are found gra- 



