Benson.— Palaeozoic and Mesozoic Seas in Australasia. 17 
a representative collection of fossils, and it must therefore be considered 
the more probable.* The fossiliferous limestone makes a large reef-like mass 
at Blinman, four hundred miles north of Adelaide, and also occurs to the 
south of that city. Here flourished some thirty-seven species of Archaeo- 
cyathinae, Kutorgina, Nisusia, Micromitra, Eoorthis, Huenella, Obolella, 
Stenotheca, Ophileta, Hyolithes, Salterella, Olenellus ?, Redlichia, and Ptycho- 
paria (Etheridge, 1890, 1919; Taylor, 1910; Walcott, 1916; Howchin, 
1918). No fossils are found in the overlying sandstones, the current- 
bedding and red colour of which suggest that they were laid down as the 
Lower Cambrian sea regressed from this South Australian trough. 
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Besides this transgression and regression of the sea into and from the 
South Australian trough there was a far more extensive flooding of the 
northern portion of the Australian continental massif. This appears to 
have been somewhat irregular in the commencement of Cambrian times, 
and there was laid down a very extensive series of conglomerates, grits, an 
sandstones, with some shales, followed by limestones now more or less 
dolomitic and silicified. This generally slightly undulating but locally 
strongly warped series extends from the Kimberley district, in the northern 
art of Western Australia, across the Northern Territory into western 
Queensland. The sediments contain Salterella, Agnostus, Microdiscus, 
Ptychoparia, and a Redlichia formerly described as Olenellus ? forresti 
(Etheridge, 1895, 1897, 1919; Woolnough, 1912; Basedow, 1914-15; 
Jensen, 1915 ; Maitland, 1919). There is no evidence to indicate whether 
the sea extended farther east than the Barkly Tableland, but it was 
* Compare also the relationship of the Lower Cambrian rocks on the Yangtse- 
kiang to the underlying glacial beds, which are “very probably" of Algonkian age 
(Walcott, 1914). 
