210 PROCEEDINGS OF SECTION C. 



The traverse would have to be kept well to the north, to avoid the 

 fault of Brushy Creek,* where the Yeringian beds are affected ; the 

 maximum throw of the fault, as Jutson points out, being 200 feet, as 

 seen at the Yering Gorge. In other Yeringian areas, especially in 

 Gippsland, this series appears to either stratigraphically overlap the 

 Upper Ordovician, or is thrust into that position. The evidence seems 

 to point to the former as the most reasonable explanation of the 

 problem, since the succession is not usually disturbed by any serious 

 teotonio movements. 



As an illustration of the variable nature of the Yeringian beds, the 

 Wombat Creek section may be cited : - f 



4. Shales and fine-grained sandstones, very fossiliferous, v/ith 



trilobites, orinoids, corals, and brachiopods. 

 3. Limestone, with corals and crinoids. 

 2. Thin bed of sandstone, with few fossils. Trilobites, crinoids, 



corals, and brachiopods. 

 1. Breccia and conglomerate, with internal casts of Atrypa 

 reticule' ris. 



The younger Silurian series defiiied by Gregory as Yeringian, 

 occurs in several of the synclines noted by Selwyn and Jutson in their 

 sections drawn across the lines of strike in the Yarra and Plenty River 

 districts. The westernmost Yeringian series appears to be represented 

 in the neighbourhood of Keilor, on the banks of the Saltwater River, 

 by some olive-brown or yellow mudstones containing numerous 

 graptolites. Amongst these are Monograptus riccartonensis, Lap- 

 worth ; M. convolutus, Hisinger sp. ; Cyrtograptus sp. ; and Retiolites 

 austraUs, McCoy. M. riccartonensis is typical of the Riccarton beds in 

 the south of Scotland, which are of Wenlock age. M. convolutus ia 

 found in the beds immediately below, or at the top of the Birkhill 

 shales. The trilobites, however, afford more definite evidence of the 

 newer Silurian affinities, for the Cheirurus and " Asaphus " mentioned 

 on the Geological Survey Quarter-sheet No. 1 N.W. are both Yeringian 

 forms in other parts of Victoria. The Cheirurus is allied to C. gibbus, 

 Beyrich, similar to a form which is characteristic of the mudstones in 

 the neighbourhood of Lilydale, and also recorded from the Yeringian 

 of Cooper's Creek, Gippsland, by Mr. Etheridge ;{ whilst the other is 

 referable to Phacops crossleii, Eth. fil. and Mitch., § described by the 

 above authors from the upper trilobite bed (? Wenlock) of Bowning 

 village. New South Wales. 



• Jut'-on Clli), p. 478. 



t Ferguson ('89), p. 17. 



} Etheridge, R., jun. ('OO), p. 23. 



S Etheridge and Mitc'i.^11 ("96), p. 489. PI. XXXIX. flga 9-11. 



\ 



