298 Proceedings of the Royal Society of Victoria. 



nearly so marked as between them and the Kalimnan. On these 

 grounds we think it advisable that a name should be given which 

 will comprise both Balcombian and Janjukian. The former series 

 is extensively developed in the Barwon basin, and the latter at 

 its typical exposure at Spring Creek, south of Geelong, is not far 

 from the borders of the same basin, so that the name Barwonian 

 is suggested. 



No geographical name that can be proposed is of course free 

 from objection on the grounds that other beds are present in the 

 area taken as typical ; but it seems advisable that a local name 

 should be employed, and the present seems a satisfactory one. 



The Basalt Plains. 



There are no points of eruption in the immediate neighbour- 

 hood which can be pointed to as the probable sources of the thin, 

 but wide-reaching, lava flows of the plains. Mount Pollock, a 

 few miles south of Inverleigh, is merely a lava-capped outlier, a 

 fact which Everett's map seems to indicate, for it is not marked 

 as a point of eruption. We hope at some future time to discuss 

 the characters of the country about here which are not made 

 clear by our preliminary examinations. The river course when 

 crossing the lava-co\ered plains is usually trenched to a depth of 

 about 100 feet about Murgheboluc, but about Native Hut Creek 

 and on the Barwon above Inverleigh the depth is less. Owing 

 to constant masking of the steep slopes by basaltic soil, the 

 thickness of the flows is rarely determinable with exactness, but 

 as shown by the frequent presence of basalt in situ in the river 

 bed, and at others by the outcrop of sandy beds at a high level, 

 the old surface was very uneven. 



The boundaries of the basalt are roughly shown on Everett's 

 map. 



The Younger Beds. 



Apart from the alluvium of the present valleys there is a series 

 of extensive sheets of sands and gravels whicli in many places 

 overlie the basalt. The country between Winchelsea and 

 Inverleigh is shown on Everett's map as covered by a uniform 

 basalt sheet, whereas, between the outlier known as Mount 



