G-EOLOGT OF TASMANIA. 73 



for brick-making and potteiy; the gravels for road-making. 

 Thovigh there has been great volcanic activity, there are 

 no signs of Tertiary lode-deposits. 



Quarternary. 

 Recent — 



3. River alluvium and sand dunes. 



2. Raised beaches and helicidce sandstone. 



Pleistocene — 



1. River drifts. 



The later terrace drifts in the valleys of existing rivers are 

 referred to the Pleistocene. Sand dunes, consolidated to 

 shelly sandstones, occur on Cape Barren, Badger, Kangaroo, 

 and other islands in Bass' Straits, containing shells of helix, 

 succinea, &c. These sandstones sometimes overlie a raised 

 beach. The raised beaches on the North Coast indicate 

 elevation within the recent period. 



The foregoing sketch does not pretend to do more than 

 merely outline the general geology of the Island. Much 

 information has been drawn from the labours of Mr. R. M. 

 Johnston, here acknowledged, but many important matters 

 still require attention. Among these are — (1) age of the 

 schists of Mounts Lyell and Read; (2) age of the horn- 

 blende schists of the Rocky River; (3) age of the quartz- 

 porphyry, or felsite, of Mounts Jukes and Darwin, and its 

 relation to the granite; (4) age and nature of the Barn 

 Bluff schists ; (5) age of the gneiss and schists of the Upper 

 Forth ; (6) connection (if any) of the Lynchford augite- 

 syenite^porphyry with the felsites on Mount Jukes and 

 Mount Read ; (7) geological occurrence of the Mesozoic dia- 

 base; (8) origin of the obsidian "buttons"; (9) connection 

 of the nepheline basaltoid rocks at Circular Head and Table 

 Cape with the prevailing normal basalts; (10) age of the 

 elseolite syenites and phonolitic rocks at Port Cygnet and 

 their boundaries; (11) origin of the lake basins in glacier 

 areas and on the Tiers; (12) the nepheline and melilite 

 rocks at Shannon Tier; (13) the occurrence of garnetiferous 

 chlorite schist in granite at St. Helens, and numerous other 

 qixestions fraught with interest to the geologist. 



These remarks may be closed by mention of the names of 

 resident geologists, to whom inquirers may address them- 

 selves for information : — In the South : Mr. R. M. John- 

 ston, stratigraphy and palaeontology ; Mr. Thos. Stephens, 

 M.A., Hobart, stratigraphy; Mr. 0. E. White, Hobart, 



