Volcanic Tuff of Pejark Marsh. 7 



some subterranean passage. As already mentioned the water is. 

 fresh, and it would require a considerable access to bring the level 

 up to the gap, which is said to have been reached in the past. 

 There is no doubt that there has been a large diminution in the 

 quantity of water in the lake Avithin recent years, and if this is 

 caused by the supply, either superficial, or superficial and sub- 

 terranean combined, as the case may be, being exceeded by the 

 loss due to evaporation, it would be noticed in the salinity of the 

 water. Keilambete has also been lowered in level to some extent 

 during the same time, but the saltness of its Avaters is very 

 marked. 



A suggestion might here be made Avith regard to this difference 

 in the Avater of the tAvo lakes Avhich in other respects seem to have 

 much in conmion. It has been mentioned that in another paper^^ that 

 at Pejark Marsh, in driving a croAvbar through the yelloAv clay, on 

 the top of Avhich cut fragments of bone AA-ere found, the bar entered 

 a softer stratum, and Avater floAved freely from the hole so made, 

 shoAving that probably the Avater-bearing bed from Avhich the local 

 residents obtain their supplies, had lieen tapped. It is also thought 

 that this might be the porous fossiliferous limestone of Tertiary 

 age exposed along tlie shores of Lake Keilamljetei for some feet above 

 the present Avater level. 



On the shores of this lake Avells have been sunk for some tAventy 

 or thirty feet in the limestone, it is said, and fresh Avater obtained, 

 although the lake Avater itself is so saline from the absence of an 

 outlet that it is unfit for consumption by stock. It, therefore, 

 seems evident that the limestone bed is a channel by Avhich the 

 supply of Avater to Keilambete is augmented to some extent. Noav 

 at Lake Terang conditions are apparently different, and the pro- 

 cess is reversed. In this case the Avater is either being forced out 

 through the porous stratum into the surrounding country, AA'here 

 numerous AA'ells are draAving it away move rapidly than l>efore the 

 stratum Avas tapped, and more rapidly than it can be naturally 

 replenished, or else underground svipplies, which were sufficient to 

 balance the loss by subterranean outlets, have been intercepted. 

 Mahony and Grayson^^ mention this as a probable factor in tlie 

 desiccation going on at Lake Te-ona:. 



The sides of the lake, or ring of hills enclosing it, are composed 

 principally of bedded tuffs. An extremely good exposure occurs 



16. Spencer and Walcott, " The Origin of Cuts on Bones of Australian Ex- 

 tinct Marsupials." Proc. Roy. Soc. Vict., Pt. I., 1911, p. 93. 



17. Loc. supra cit., p. 10. 



