64 GEOLOGY OP TASMANIA. 



The horizontal beds of conglomerate, which lie as heavy 

 caps on the Dial Range and most of the Western Moun- 

 tains, have been assigned to this system. These massive 

 conglomerates crown Mount Farrell. Murchison, Lyell, 

 Owen, Jukes, Roland, Claude, &c. 



Permo-Carh oniferous. 



These rocks consist of sandstones, mudstones, grits, con- 

 glomerates, and limestones, with shales and thin coal seams. 

 The most productive coal measures in Tasmania do not be- 

 long to this system, but are Upper Mesozoic, probably 

 Jurassic. The Permo-Carboniferous strata have been 

 thoroughly examined by Mr. R. M. Johnston, and his classi- 

 fication is adopted : — 

 Upfer — 



7. Elaeolite syenites, phonolites and trachytes, at Port 



Cygnet. 

 6. Southport, sandstones and shales. 

 5. Mount Cygnet and Adventure Bay, sandstones and 



shales. 

 4. Upper marine mudstones overlying Mersey coal ; 



Porter Hill shales and sandstones, Sandy Bay. 

 3. Lov/er coal measures, Mersey Basin. 



2. Tasmanite shales. 

 Lower — 



1. Lower marine mudstones, limestones, conglomerates, 



and grits, throughout S.E., N.E., and Midlands. 

 Conglomerates, grits, and micaceous sandstones and slaty 

 flagstones, in thick beds, form the base of the system. These 

 conglomerates, at One Tree Point, North Bruni, at Darling- 

 ton, the northern point of Maria Island, below the lime>- 

 stone beds, contain large blocks of granite, porphyry, &c. 

 The angular blocks on Maria Island are over a ton in 

 weight, and on Bruni, too, they are very large. The Lower 

 Marine series of limestones and mudstones comprises, in 

 Southern Tasmania : — 



3. Fenestella mudstones, at Porter Hill, The Grange, 



Cascades, &c. 



2. Spirifera and strophalosia mudstones, Huon Road, 



&c. 

 1. Limestones, on Maria Island, at Bridgewater; also 

 at Fingal, Middle Arm, &c., in the North. They 

 contain favosites, sfirifera, 'productus, conularia, 

 pachydomus, notoniya, aviculopecten, &c. 

 These marine beds occur all along the Derwent, from Bruni 

 Island to New Norfolk. At Porter Hill, soiith of the Alex- 

 andra Battery, on the Brown's River Road, sections are ex- 

 posed of the lower marine series, with its common fossils,, 



