PBBSIDBNT'S address SECTION c. 177 



found a few trilobite remains which were named Dinesus ida by Mr. 

 Etheridge, who regarded it as having affinities with Cambrian 

 forms, and tliese Dines as beds, cherty in part, were for 

 a time described as Cambrian. A later find of more trilobite 

 fragments was examined by Prof. Gregory, who described a 

 new genus Notasaphus. Some obscure markings resembling Bryo- 

 graptus were later referred to algae, and poorly preserved 

 Brachiopods were regarded by Mr. Chapman (18) as Ordovician, and 

 even showing affinities with the Upper Oi'dovician. With this addi- 

 tional evidence Prof. Gregory regarded it as safer to include the 

 Dinesus beds as forming the lowest part of the Ordovician. 



My own search resulted in the finding of Radiolaria in the black 

 cherts, and also in some of the Dinesus beds. Some indeterminable 

 sponge spicules were also noted in this series, and a few feet above what 

 had been mapped as their upper limit, while numerous spicules of 

 Protospongia wei'e found in the Dinesus series and in the Ordovician 

 rocks just west of them. I find that Mr. Etheridge has recorded Proto- 

 spongia as occurring with Dinesus ida. (Geol. Surv., Vict., Month. 

 Prog. Rep., Feb., 1900, p. 23.) This genus occurs with the L. Ordo- 

 vician graptolites of Lancefield, so that there seems no valid reason on 

 the available evidence to regard the Dinesus series as other than L. 

 Ordovician. The black cherts and diabase which immediately underlie 

 them I regard for the reasons given above as conformable with them. 

 It is possible that they may be U. Cambrian, and that there is here 

 a conformable passage between Cambrian and L. Ordovician, but in 

 the present state of our knowledge it seems to be safer to regard them 

 as forming the base of the Ordovician series in Victoria. If the term 

 Heathcotian is to be retained in Victorian geology, it would, I think, 

 be better to define it not as a distinctly Pre-Ordovician series but as a 

 new horizon of the Lower Ordovician whose cherty upper limit passes 

 into the Lancefield series, while its lower limit would be defined as the 

 base of the diabase series. Palieontologically it should, I think, 

 include not only the Radiolaria in the cherts, but also the fossils of the 

 Dinesus beds — namely, Dinesus, Notasaphus, Protospongia, and other 

 sponge spicules, Radiolaria and the Brachiopods identified by Mr. 

 Chapman, viz. : — Siphonotreta (2 species), Chonetes concinna, sp. nov., 

 Strophomena flabelloides, sp. nov., five species of Orthis, Camaro- 

 toechia (?), and the bivalve Modiolopsis (1), knowsleyensis, sp. nov. 



Evidence from, other Areas in Victoria. 



In some of the areas referred by Mr. Dunn to the Heathcotian, 

 cherty rocks occur unaccompanied hy diabase, and some of these areas 

 have since been shown to belong to younger series. 



]Vear Edi, on the King River, black slates with turquoise have 

 yielded graptolites (25), including Diplograptus, Didymograptus, and 

 Glossograptus, and have been referred by Dr. Hall to the Upper Ordo- 

 vician. 



Mansfield. — The phosphate deposits near Mansfield described by 

 A. M. Howitt (26) are associated with black cherts and dark shales. 

 Trilobite fragments and other organisms from them have been 

 examined by Prof. Gregory, and he has referred them (9) to Olenellus 



