268 OCCURRENCE OF DIATOMACEOUS EARTH. 



being recognized by D. Billings." . . , {Op. cit. p. 627) 

 " The extreme temperature at which v^egetation has been observed 

 is 200° F., recorded by Prof. W. H. Brewer at the California 

 Geysers." 



It is clear therefore that Diatoms are capable of flourishing in 

 the waters of hot springs, the water of which must necessarily be 

 more or less highly mineralised, though apparently they do not 

 flourish in water at so high a temperature as that in which some 

 algte, such as the Oscillatorue, can flourish. The fact must not 

 be forgotten that spicules of Spongilla are at the Warrumbungle 

 Mountains associated with the Diatoms, and obviously if the 

 Diatoms flourished in hot water the Sponges must have existed 

 under similar conditions. 



Animal life was well represented in the neighbourhood of 

 Eurnas by Rhizopods, but no mention is made of freshwater 

 sponges. 



It is at all events certain that at the Warrumbungle Mountains 

 the Diatom Melosira and a variety of Sponffilla occur in associa- 

 tion with trachytic lavas and tuffs of early Tertiary, possibly of 

 late Cretaceous Age. 



EXPLANATION OF PLATES. 



Plate XV. 



Section showing junction between the Trachyte Volcanic Group of tlie 

 Warrumbungle Mountains, and the Permo-Carboniferous Coal Measures in 

 a tributary of Uargon Creek, Wollongulgong, near Tooraweena, N.S.W. 



Plate XVI. 

 Uj^per Figure. 

 Section in Wantialable Creek, near Tooraweena, Warrumbungle Moun- 

 tains, showing intercalation of Diatomaceous Earth in the Traciiyte Series. 



Lower Figure. 



Section in Wantialable Creek, near Tooraweena, Warrumbungle ]\Ioun- 



tains, showing Diatomaceous Earth in association with Cinnamomum 



Leichhardtii. 



Plate xvii. 



Ginnamomum Leichhardtii, Ettings. 



