Volcanic Necks at Aiiclerson's Inlet. \6^ 



Division 2. — Between the source of the Powlett and theTarwiu 

 Rivers the country consists of undulating plains, rising to the 

 height of over 300 feet above sea level near Leongatha, and 

 extending to the Southern Ocean and Anderson's Inlet, either 

 gradually, as along the valleys of Pound, Screw and Wreck 

 Creeks; or terminating abruptly in cliffs up to 100 feet high, as 

 along the coast from Wreck Creek to west of Cape Paterson. 



Geology. 



Division l. — The country between the Bass and the Powlett 

 Rivers, with the exception of a small area to be mentioned later, 

 consists almost wholly of felspathic, argillaceous, calcareous and 

 carbonaceous sandstones, shales and mudstones of the Jurassic^ 

 system. They contain numerous seams of good black coal. These 

 seams are chiefly thin ones, varying from less than one inch to- 

 six feet. Within this area are situated the Victorian Coal Fields 

 of Outtrim, Jumbunna and Korumburra. 



Dispersed throughout the district, particularly in the basin of 

 the Foster, are numerous localised volcanic occurrences, compris- 

 ing plugs and dykes of dolerite and basalt, with apophyses there- 

 from, representing the necks of old volcanoes. They vary in 

 extent from the largest reaching a surface area of about 30 acres, 

 to the smallest, occupying but 3 square feet. The exception 

 previously referred to is an area of about 250 acres at Kongwak 

 on the Foster, where an inlier of Silurian occurs. 



Division 2. — The country between ' the Upper Powlett, the 

 western tributaries of the Tarwin, and the Tarwin itself is diverse 

 in character. 



Around Leongatha and north of Ruby it is mainly of volcanic 

 origin, comprising laterite, flow l)asalts and tuffs. There are, 

 however, strips of pebbly gravels, and these, and the volcanics 

 rest on Jurassic sandstones near Ruby. These gravels belong- 

 to the Cainozoic system. 



Division j. — Between the Middle Powlett (that part of the 

 valley .south of Outtrim), Anderson's Inlet, and the Lower Tarwin 



1 These strata were formerlj' referred to by the Geological Sur\ey of Victoria as 

 .Jurassic, and later on as Trias— Jura. A reversion to the former name has, however, now 

 been made. 



