30 



THE UEOLOGIST. 



particular conglomerates I am describing would, however, appear to pre- 

 sent somewhat different conditions, the barren portions being at the bot- 

 tom and the shelly masses forming the upper stratum, — suggestive, per- 

 haps, that the shells, being light and comparatively large, took a superior 

 position, whilst the more weighty sand was washed or shaken through, on 

 the principle that causes the larger and unbroken biscuits, if I may be al- 

 lowed the simile, to occupy the upper part of a cask, while the dust and 

 "midshipmen's nuts " just as assuredly seek the bottom. 



In consequence of the foldings and contortions to which these Silurian 

 beds have been subjected, as may be supposed, a great variety, both of 

 fossils and litbological characteristics, are crowded into a comparatively 

 small space. JSTear the Botanical Gardens, situate on the southern banks 

 of the Yarra-yarra, and not far removed from two of the Elvan dykes 

 marked on the map, the strata are composed of soft micaceous sand- 

 stone, generally friable, and apparently much broken up and dislocated by 

 past convulsions. 



The fossils in this locality are numerous, but small in size ; Orthidse, 

 Leptssnse, with a kind of spiral univalve, probably a Euomphalus, being 

 the prevailing types. Close beside the beds wherein these organisms pre- 

 vail are others destitute of fossils, but containing nearly spherical bodies 

 of perhaps half an inch in diameter, and generally having a badly defined 

 stem-like projection on one side, the stem being sometimes continued for 

 several inches, until ultimately lost in the surrounding matrix. On being 

 newly fractured, these bodies appear of a fine lake colour, mottled with 

 lighter tints, but fade and become dim after a few days' exposure to light 

 and air. They are not yet named in the University Museum, although 

 some few are therein exhibited. An infiltration of peroxide of iron and 

 manganese may perhaps account for both the colour and the phenomenon ; 

 but it is questionable whether these latter substances may not have been 

 attracted by some animal or vegetable remains forming a nucleus, which 

 has since disappeared. 



In a quantity of stones recently excavated from a sewer communicating 

 with the Parliament Houses and Treasury — a manor particularly poached 

 over by myself — I have met with Holopella? (?), Orthidse (very small), 

 Cuculella? (the shells still attached to each other, but generally open and 

 filled with the surrounding stone), broken fragments of an Orthoceratite 

 with transverse corrugations, Trilobites, and C)*eseis Furbesii. These 

 latter pteropods, I believe similar to a species now found in the Mediter- 

 ranean, are especially numerous. The general size is 1^ to 2 inches, al- 

 though one specimen, unfortunately fractured, must have been nearly 5| 

 inches in longitudinal dimensions. 



The above are nearly always found in the soft sandstones of the locality, 

 whilst the shales of the same place contain large quantities of a species of 

 worm many inches in length, which I do not find depicted in any work on 

 the Silurian deposits in my possession. 



At Carlton Butts, about 1^ mile north-east of Melbourne, the fossils, 

 although thinly scattered, are remarkable for being in a remarkably fine 

 state of preservation. Shales and sandstones predominate in this locality 

 also, but are much harder than in the place last described. A peculiarity 

 of the fossils found in this spot is their singularly rich colouring when 

 only recently obtained. On laying open, at a single blow of the hammer, 

 a fine specimen of the tail portion of an Asaphus (?), as it appeared a 

 beautifully sculptured and lake-tinted object on the cream-coloured mass of 

 surrounding stone, I almost thought the fossil some new species of moth or 

 butterfly miraculously imprisoned in a rocky matrix. The colouring is not 



