.:8 R. Henry WalcotI : 



just at the back of the Mechanics' Institute, where they have been 

 ■quarried for building stone, and a clean vertical fcae about ten 

 feet in height has been left. The beds here are of much coarser 

 texture than at Pejark Marsh, and scattered througii them are 

 small lumps of white, indurated clay, which impart the effect pro- 

 duced by splashes of whitewash. An interesting feature was 

 noticed here near the top of the beds, giving evidence that a vol- 

 canic vent was not far distant. This was the characteristic bend 

 in the bedding of the tuff caused by impact of a falling body, and 

 occurred under a cavity at one time occupied by a bomb or ejected 

 block. 



At Mt. Terang, where the tuff is lieing quarried just to the 

 north of the summit, the beds are seen to be dipping, as far as can 

 be made out, with the outward and northward slope of the hill. 

 They are capped by a thin flow of scoriaceous basalt, which seems 

 to form the cover of the hills extending to the west. Clay en- 

 closures are also noticed here, but not so abundantly, and in one 

 place the lava has intruded the tuff in the form of a small dyke 

 now largely decomposed. 



Just south of the summit of Mt. Terang, where a cutting for a 

 road has been made, from what can be seen, the beds generally 

 show a dip towards the lake, but as they have here been disturbed 

 and become almost vertical within a short distance, Avhere they 

 abut on a coarse agglomerate or mass of volcanic ejectamenta, it 

 IS not quite certain whether this is the true direction of dip or 

 not. It may be that this agglomerate is occupying a vent, and 

 that the disturbance and rapid change in dip of the bedded tuffs 

 has been caused by the downward drag of the volcanic material 

 •during its settlement. Enclosed in the agglomerate are lumps of 

 iiesh-coloured clay, reaching up to the size of a man's head. They 

 are indurated by the heat to which they have been subjected, and 

 mostly exhibit an imperfect prismatic structure from the same 

 cause. These enclosures are of considerable interest on account 

 of the fossils some of them contain, bearing witness of the presence 

 of the marine tertiary beds underlying the volcanic deposits of the 

 district, and from which they have been derived. Mr. F. Chap- 

 man identified these fossilsi as belonging to two Polyzoan genera — - 

 Adeona and Lepralia, and a brachiopod, doubtfully referred to the 

 genus Cranicu. If then, we have here no evidence that the site 

 of an old vent lies within the limits of Lake Terang, from wlienco 

 came the various materials forming the mount and the surround- 



