318 PUOCEEDIXGS OF SECTION C. 



11.— RECENT ADVANCES OF OUR KNOWLEDGE OF VICTORIAN 



GRAPTOLITES. 



By T. S. HALL. M.A., D.Sc, Melbourne University. 



In 1899 I summed up our knowledge of Victorian graptolites* irt 

 a paper contributed to the " Geological Magazine." Since then a large 

 number of graptolites have passed througli my hands, and have been 

 dealt with in the Proceedings of the Eoval Society of Victoria and 

 in the Records of the Geological Survey. The sequence that was estab- 

 lished in my earlier paper is as follows : — - 



Silurian. — Characterised by Monograptus, Cyrtograptus (F. 

 Chapman in Nat. Mus.), Retiolites, Diplograpttts (1). 



Ordovician. — Upper: Characterised by Dicranograptus, Dicello- 

 graptus, Leptograptus, Neniagraptiis, Didymograptus (rare), Diplo- 

 graptufi, ClimacograjJtus, Cryptograptiis, Glo>sSograptus, Lasio- 

 grapUis, Retiograjdus, BetioJites. Lower : Characterised by Clono- 

 graptua, Bryograptus, Dichograptus, Tetragraptus, Didymograptus, 

 Dictyonema, Qlosmgraptus., Lasiograplus, ifec. 



Verj^ little has been added to our knowledge of the Silurian 

 species and of their distribution. Monograptus duhius has been 

 identified and figured, and a fairly large ai"ea near Matlock has been 

 definitely fixed as of Silurian age. In the Upper Ordovician, abutting 

 on the Silurian and to the west of it, an extensive area of rocks of 

 this age has been proved by the collecting of Mr. Wm. Baragwanath, 

 who surveyed the district. The fauna proved rich, and in a fairly 

 good state of preservation. It has been dealt with in the " Records 

 of the Geological Survey." East of this area, as already mentioned, 

 .Silurian comes in. The other limb of the geosyucline vrith an almost 

 identical fauna comes up along the Wellington River, where Mr. E. 

 0. Thiele secured a fine collection. This has been supplemented by 

 other collectors. Dicranograptidae are abundant and varied, and just 

 lately- ISi emagraptu.i gracilis, J. Hall, has been found. Stray fossils of 

 similar age have been gathered along a comparatively narrow belt 

 striking north-westerly from here. The Matlock Upper Ordovician area 

 is in the middle of what has hitherto been regarded as Silurian 

 country, and the Wellington River series in Devonian. Everett's, 

 8-in. map consequently needs revision here. The boundaries of the 

 Ordovician, to the east again of the Silurian, are not well defined, 

 but from numerotis scattered observations it is clear that Upper 

 Ordovician, as characterised by Dicranograptidoe, alone is repre-- 

 sented. This Upper Ordo-\acian belt strikes northwards into New 

 South Wales as far at any rate as Orange. 



Our Lower Ordovician graptolite distribution is better known, and 

 our knowledge lias lately been considerably added to. The division in- 

 dicated in ray previous papers is : — ■ 



Lower Ordovician. — DarriwiUian : Characterised by Glossn- 

 graptus, Lasiograptus, &c. C astleniainiaii : Characterised by Logann- 

 graptuf', DidymograjJtus cadiiceus, D. hifidus, kc. Bendigonian : 

 Charaote.rised by Tetragrapttis fruticosus, T. pendens, T. serra, T. 



Geol. Mag.. 1S09. pp. 1.^8-4.51. 



