7oOcT., 1912.] Xoh' on Limestone Deposits in Victoria. 



599 



The analyses of the deposits show them to be of great purity with one 

 exception, viz., Duck Ponds, ^^'oornyaloak. 



It should be noted that the ('oimadai deposit is dolomitic, containing 

 over 40 per cent, magnesia, which, according to authorities, somewhat 

 tletracts from its usefulness for agricultural purposes. 



In addition to the limestone deposits mentioned above, there are marl 

 beds, consisting mainly of calcium carbonate in an amorphous form, scat- 

 tered through the limestone eras of the State, several of which are being 

 quarried for agricultural purposes. 



Some of these are situated in the Geelong district, whilst others are 

 at Cobden. The following analyses of marl, from Mount Duneed and 

 Cobden, may be of interest — 



Marl from Ford's Pit, Mt. Duneed. 



Soft marl deposits have also been discovered in the Gippsland district. 

 The following is an analysis of a sample from the Gipp.sland Lakes — 



M.\RT. FROM NiCOLSON RiVEE. 



Insoluble 



Fe.Oj-AUOs 



Lime 



(= Ca. Carb.) 



Magnesia 



(= Mg. Carb.) 



As will be noticed from the tables marls vary in lime content, and as 

 a general rule white marls are the purer. The impression that the blue 

 pug underlying the.se deposits contains the most lime is erroneous, and 

 should be dismissed. 



7o 



2-47 

 104 

 51-88 

 92-64 

 0-91 

 1-91 



