PROCEEDINGS OF SECTION C. 213' 



warm temperate and tropical seas of China, Japan, the Philippines^ 

 and Australia. In the Melbournian series of Victoria, Lingulaisan 

 abundant palaeontological factor, and its presence there undoubtedly 

 points to the moderately high temperature of the Silurian sea of this 

 part of the world. Curiously enough, Lingula is almost absent from 

 the next, the younger stage, or Yeringian ; but there its absence may 

 be accounted for on the ground that this brachiopod is now found in 

 the laminarian and littoral zones. For, whilst the Melbournian fauna 

 indicates a generally shallow, muddy or sandy accumulation, the 

 Yeringian, by its reef-formed limestones and comparatively deep- 

 water mudstones, possibly represents a more profound bathymetrical 

 condition. The corals, also, in the Melbournian are rare, and repre- 

 sented only by simple forms, as Streptelasma, if we except a single 

 occurrence of a cyathophylloid example found in the Moonee Ponds 

 Creek sandstone. The Yeringian corals , on the other hand, constitute 

 an important factor in the life of that period. For example, there 

 are massive reefs composed of Favosites, compound cyathophylloids, 

 and the gigantic stromatoporoids. These give e\ndence of clear water^ 

 and also point to rapidly subsiding areas, as exemplified in the present 

 day coral reefs, as well as indicating a generally warmer temperature 

 of the water than that which prevailed in the Melbournian sea. 



It is true that, in the presence of abundant Girvanella in the 

 Yeringian, we have evidence of the proximity of the shore-line, yet the 

 areas in which these blue-green algae flourished were undoubtedly free 

 from scour and argillaceous sedimentation, such as would be met with 

 in the older Silurian seas. The strongly marked current bedding seen 

 in the Melbournian mudstones is only met with rarely in the Yeringian ; 

 and the tubes and crypts of the errant worms, as Trachyderma, are 

 oert^iinly more abundant in the rocks of the older stage. 



Other Silurian Faunas. 



There are innumerable interesting data to be gleaned from a 

 oomparison of the Victorian with other Silurian faunas. To state the 

 case briefly, the older, Melbournian faunas," seem apparently to have 

 been better developed in the State of Victoria than in any of the other 

 States in which Silurian rocks occur, as, for example, in New South 

 Wales and Queensland. Tasmania and parts of New South Wales, 

 especially in tho- lower part of the Bowning and Yass series, appear, 

 however, to be correlative in age with our Melbournian. But the larger 

 part of the New South Wales Silurian is clearly equivalent to the 

 Yeringian stage in Victoria. In support of this statement such groups 

 as the corals, brachiopods, and trilobites supply ample evidence, for 

 many of the species first described from New South Wales are con- 

 stantly brought to light in rocks of newer Silurian age in Victoria. 



