246 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [Feb. 24, 



At Mr. Hull's limestone quarries at Tolosa, about four miles from 

 Hobarton, I found dark grey limestone, sometimes compact, some- 

 times finely laminated, with fragments of shells and corals. The 

 beds of limestone were about two feet thick, and in one place were 

 some beds of soft brown sandstone interstratified with thin beds of 

 limestone. These sandstones were scarcely consolidated, and fell to 

 pieces on being taken from the quarry. They often contained fossil 

 shells, both Spiriferi and Productse, quite perfect in appearance, but 

 so much decomposed as not to bear extraction, falling into white 

 powdery fibrous carbonate of lime. I procured from other parts of 

 these quarries the following fossils : — 



Fossils from Mr. HulVs Quarries. 



Corals. 



Stenopora Tasmaniensis. Fenestella internata. 



informis. fossula ? 



Fenestella ampla. Caryophyllsea.. 



Mollusks. 

 Producta rugata. Spirifer Stokesii. 



brachythserus. -Vespertilio. 



Spirifer subradiatus. avicula. 



Darwinii. Pecten squamuliferus, 



— — Tasmaniensis. Limseformis. 



A few miles above New Norfolk, the banks of the Derwent showed 

 cliffs consisting of alternations of sandstone with black and brown 

 shales, producing a precise resemblance to parts of the English coal- 

 measures. Much fossil wood, apparently parts of large trees, lay in 

 these rocks. 



Similar rocks to these were frequently observed in the cuttings of 

 the road-side as far as Oatlands in the centre of the island, and they 

 almost invariably lay in positions so nearly approaching horizontality, 

 that their dip was not appreciable to the eye. Still their continuity 

 did not appear to extend unbroken over any large district, as not only 

 were dykes and other masses of intrusive trap rocks frequent, but 

 solid ridges of crystalline greenstone often intervened, and evidently 

 cut off one portion of the palaeozoic rocks from the other. 



In the immediate vicinity of Hobarton there were places, as near 

 Stoke, and at the mouth of the valley of Risdon, where the palseozoic 

 rocks had evidently been tilted up and altered by masses of trap rock, 

 which could be traced to have a perfect passage from compact tabular 

 or amorphous basalt into hills of solid crystalline greenstone. 



In other places quarries were opened in sandstones of the palaeo- 

 zoic age, forming small patches either embosomed in greenstone, or 

 resting upon it. About a mile from a place called Ralph's Bay Neck, 

 on the S.E. side of North Bay, I found a cliff where the sandstones 

 were shown clearly to be posterior to the igneous rock. In this case 

 a dark, rudely columnar trap rock ended in a succession of small 

 cliffs and terraces in one direction, upon which terraces and against 

 which little cliffs rested the sandstone perfectly undisturbed, and 

 evidently in the position in which it had been originally deposited. 



