BY T. W. EDGEWORTH DAVID. 491 



Yegetahle Secretion Theory. — This theory was advanced by Mr. 

 W. A. Dixon in his paper already quoted (pp. 135 and 136), and 

 the similarity in the chemical composition of some waxes of living 

 plants to that of kerosene shale, as Mr. Dixon points out, lends 

 some weight to this argument. 



It may be not out of place here to mention that Mr. Hamlet, 

 F.C.S., the Government Analyst, stated at the last meeting of the 

 Royal Society that the fact had lately come under his notice that 

 a considerable quantity of oil had lately been observed to be 

 floating on the surface of the reservoir at the waterworks at West 

 Maitland. This oil, in Mr. Hamlet's opinion, was produced by a 

 small aquatic plant, Spirogyra or ProtococGus, but he was not pre- 

 pared to say whether the oil was secreted by the plant, or whether 

 it was connected with fructification. He was inclined to the 

 former opinion. 



Coorongite Theory. — The author is informed by Mr. C. S. 

 Wilkinson that he believes that it has been suggested that 

 kerosene shale may have had an origin similar to that of the 

 Coorongite found at Coorong, in South Australia. The author, 

 however, has been unable to find any reference to such suggestion. 



Coorongite is described by W. T. Thiselton Dyer, B.Sc, 

 F.L.S.,"^ as "a peculiar indiarubber-like material, . . . the 

 history and origin of which seem likely to become matters of as 

 great controversy as the true nature of the Torbane Hill Mineral. 

 In appearance it consists of sheet-like masses somewhat less than 

 an inch in thickness, and with more or less scattered sand-grains 

 adhering to their surface. It occurs at a place called Coorong, 

 whence it is brought to Adelaide. The country in the neighbour- 

 hood is described as consisting of limestone ridges and scrub 

 without grass. The Coorongite, as it has been named, is con- 

 fined to a depressed portion of the district, the bottom of which 

 is sandy and grass-covered ; it occurs on the banks forming the 



* " On a Substance known as Australian Caoutchouc." Journal of 

 Botany, 1872, pp. 103, 104. 



