4 B- Henry Walcott : 



yet supplied evidence of a sufficiently definite nature to prove that; 

 the tuff emanated from it. Mahony and Grayson^ say that tuff was 

 proved in Avells sunk through the basalt to the north of the Mount, 

 and they verbaly informed the -writer that there was also evidence 

 of tuff underlying the lavas in other directions. 



This merely introduces the possibility of Mount Noorat having 

 contributed to the Pejark tuff, but one of the other suggested places 

 of origin' is accompanied by evidence quite sound enough to fix it 

 as the main source. 



Lakes Keilambete and Terang, although surrounded by accumu- 

 lations of tuff, have not been generally accepted as the sites of old" 

 volcanic vents. 



Mr. A. R. C. Selwyn5 thought they were more probably acci- 

 dental depressions due to other causes, and Professor J. W.. 

 Gregoryio is confident that they, as well as Lakes BuUemerri and' 

 Gnotuk, are not crater lakes, but occupy basins formed by sub- 

 sidences in bedded volcanic tuff, which were probably caused by the- 

 eruptions of neighbouring volcanoes. 



Mahony and Grayson, i^ on the other hand, hold that all these 

 lakes are directly due to volcanic explosions, and with this view 

 the writer is in accord. Their paper is a most valuable one, not 

 only on account of the interesting matter it contains, but also be- 

 cause it is the only systematic account of the geology of the district 

 yet published. As these notes must necessarily be brief, and only 

 of a general nature, reference should be made to that paper. 



The part of Lake Keilambete visited by the writer, like nearly 

 the whole of its banks, was hidden by a luxurious growth of grass, 

 with the exception of some outcrops of soft, tertiary, fossiliferous 

 limestone underlying the superficial tuffs. ^^ 



S. Loc. supra cit., p. 6. 



9. Intercolonial Exhibition Essays, Melb., 1866. 



10. The Geography of Victoria, Melb., 1903, p. 130. Revised Ed., 1913, pp. 

 131-136. 



11. Loc. supra cit., p. 13. 



12. Mr. P. Chapman, Palseontologist to the National Museum, who was good- 

 enough to examine all the fossiliferous material collected, determined 

 the Lake Keilambete forms from the limestone as follows : — 



Foramnifera. — ■TruncaUMna lobatula, W. and J. sp. Also others 

 indet. 



Polyzoa. — Indet. 



Echinldermata. — Echinocyamtis (SciiteUina) patella, Tate sp, 

 Eupatagus (?) laubel, Dvmcan. 



Brachlopoda. — Magellania insoUta, Tate sp., and M. (?) pectoralis- 

 Tate sp. 



Pelecypoda. — Pecten yahliensis, Tate. 



Pisces. — Lamnu apiculata. Ag. s\). 



Mr. Chapman places the limestone bed in the Janjukian series. 

 Oyster shells of fossilized appearance occur on the beach of the lake, 

 and it mav be useful to record the fact here given to the writer by 

 Mr. H. Quiney, of Mortlake, that many years ago an attempt was made 

 to acclimatize oysters in the lake, but without success. It is to this 

 soui-ce that the "presence of the shells may be attributed. 



