Victorian Fo.ssils, Part VII. 97 



Whilst showing certain characteristics in common with T. ver- 

 rucosus, T. egertoni, and T. salteri, the species now named 

 T. magnificus differs in the wide, laterally extended, fused 

 posterior elements of the body-covering ; in the extremely 

 pronounced tubercular ornament, and the sometimes hollow or 

 perforate character of the tubercles ; and in the extraordinarily 

 large size of the head-shield as compared with all known examples 

 of Thyestes. The width ratio of T. magnificus is as 2:1 in com- 

 parison with the measurements of a specimen of T. verrucosus 

 given by Rohon\ and as 4:1 compared with a specimen of T. 

 egertoni in the collection of the National Museum. 



Occurrence. — This interesting and unique specimen was fuund 

 in the Silurian (Yeringian) mudstones of Woml)at Creek, a 

 tributary of the Mitta Mitta River, N.E. Gippsland. 



At this locality the Silurian locks rest unconformably on the 

 Upper Ordovician slates and sandstones, the slates of the latter 

 group containing Climacograptus bicornis, J. Hall, var. longispiiia, 

 T. S. Hall; Dicellograptus elegans, Garruthers; and D. cf. morrisi,. 

 Hopk. 



The downward succession of these beds, resting on Ordovieiaii 

 strata, is as follows'^ : — 



4 Shales and fine-grained sandstone, very fossiliferous — 

 with Trilobites, Crinoids, Corals and Rrachiopods. (This bed 

 in all probability yielded the fi.sh remains"). 



3 Limestone — with Coi-als and Crinoids. 



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

 Crinoids, Corals, and Rrachiopods. 



1 Rreccia and conglomerate — with internal casts of Atrypa 

 reticularis. 



From the general facies of the fossiliferous Silurian rocks 

 exposed at Wombat Creek, it is highly proVjable that the several 

 l)eds may all be included in the uppermost or Yeringian series. 



A noteworthy feature, in common with similar Silurian rocks 

 of other localities, where the junction of the Silurian and Upper 

 Oixlovician can be seen, is the absence of the lower, Melbournian^ 



1 Op. supra cit. 



2 See Ferguson, W. H. Monthly Progress Report, No. 3, 1889, p. 17. 



3 Mr. Ferguson has since confirmed this opinion. 



