142 Chapman, The Palcvozoic Flora. [voi.'^xxxiv 



From the associated Ayclucocyathincc in the Umcstonc, this 

 algoid species belongs to the Lower Cambrian, and, in fact, is 

 closely related to another of the same genus found in the Lower 

 Cambrian of Siberia by Van Toll. 



In Ordovician times the Australian coast-line covering parts 

 of South Australia, Victoria, and New South Wales, as well as 

 Tasmania, was fringed with extensive black mud-flats and 

 shallow seas, in which flourished abundant growths of the 

 plant-like animals called Graptolitcs. Remains of undoubted 

 plants, however, seem to be unknown in these beds, the Grapto- 

 lites either superseding the plants in tliis area or else surviving 

 the ordeal of fossilization by their more -durable chitinous 

 peridermic covering. That sulphur bacteria must have been 

 present in these dark shales is fairly evident from a study of 

 the conditions prevailing at the present time in an area like 

 the Black Sea,* and, in fact, whilst examining some very thin 

 slices of Victorian ()rdo\-ician slate under a high power, I was 

 struck by the appearance of some minute ol)jects having a 

 resemblance to certain fossil bacilli found in a coproUte of 

 Permian age by Renault and Bertrand.f These bodies are 

 long, sausage-shaped, slightly curved in some cases, and measure 

 I m. in diameter. As in modern land-locked areas, there also 

 probably existed a plankton consisting of lower animal organ- 

 isms and diatoms. 



Passing upwards to Siluki.\.\ times, large tracts of the 

 Australian continent were covered with shallow to moderately- 

 deep seas, especially in southern and central Victoria, in 

 southern and central New South Wales, in Queensland, and the 

 Northern Territory. The oldest Silurian is that of the Mel- 

 bournian division, equivalent to the Llandovery or Valentian 

 of Europe, and probal)ly almost confined to the Melbourne 

 bed-rock and tiie sandstone of Heathcote, although some 

 locally-developed beds in New Soutli Wales may turn out to 

 l)e of similar age. In these shallow seas were deposited sand- 

 stone with false bedding, and pyritous and hnK^iitic nuidstones. 

 Later on, in Yeringian times, the ("(luivalent of the Wenlockian. 

 deeper water conditions seemed to have predominated, as 

 seen in the coral limestone of Lilydale and Waratah Bay, Loyola, 

 and Toongabbie, in Victoria, and of the I'ederal Territory in 

 New South Wales. The shallow water and marine deposits ol 

 both Melbournian and Yeringian stages contain numerous 

 fucoids referred to the genus livlhnlrcphis. There is some 



* See Scliuchert, " I'mc;. Amer. I'liil. .Soc," vul. liv., 1915, p. 259 ; also, 

 Andrussow, " La .Mcr. Noire," Guides des Excursions, V'lle., Conj;. (Jeol. 

 Internal. .Si. Petersbourg, 1897, Art., xxix. 



t " Compt. Rend.," vol. cxix., 1894, \>. 377; ai.st*, Seward, " Fossil I'laiits," 

 vol. i., 1898, \). 135, fig. 28*. 



