54 W. J. Harris : 



mon later, while Triyonograptus, Oncograjitus, LosiograpHis, and 

 Glossograpfus appear still later. The Upper Ordovician and Silu- 

 rian graptolites are quite distinctive. Only the broadest outline 

 seems possible at present, and conclusions drawn from observations 

 on one side of the world may not be applicable to conditions on the 

 other. For example, Elles, Wood and lluedemann^ all agree in 

 derivint;; Dicliogvaptiis octohrachidtus from Loganograptus logani^ 

 In Victoria, as Dr. Hall^ has pointed out, the order of occurrence is 

 reversed, for while B. ocfohrachintiis is found in Upper Bendigo 

 beds, Loga/iograpfus is Upper Castlemainian. Differences such aa 

 this in the distribution of genera make one hesitate to generalise. 



VI. Dp. Hall's Classification of Castlemaine 

 Graptolites. 



The following classification is that given in Dr. Hall's paper on 

 the Geology of Castlemaine. ^ The zones are arranged in descend- 

 ing order as there set out. 



1. Zone of Loganogra,ptus logani. 



2. Zone of Didi/mograptus cadiiceiis. (Victoria Gully Beds.) 



3. Phyllograpf o-cad uceus zone. 



4. Burns' Reef beds. (Fln/Uogiaptus ti/pits, with no predo- 



minant associates.) 



5. Zone of Dldymograptus bifidiis. (Wattle Gully Beds.) 



6. Zone of Tefragrapfvs fruficosus. 



The facies of eacli zone is not given in detail, though it is briefly 

 discussed. In anotlier place Dr. Hall* states that " rhi/llograpfui 

 typus long persists and is survived a short time by P. angustifolius. 

 Specimens of Diplograpius appear in the higher beds but not appar- 

 ently in the lower. A species of Clonograptus occurs in the lowei* 

 beds, but soon disappears. Loganograptus logani puts in an 

 appearance in the higliest zones, and ranges into the Darriwil 

 series." 



VII. Proposed Revised Classification. 



The table recorded below^ shows the classification projjosed. The 

 beds are arranged in descending order and Dr. Hall's numbering 

 is retained to I'ender comparison easier. Beds above the Castle- 

 maine series are prefixed with the letter " A." 



1 Graptolites of New York, I. N.Y. Mus. Mem. 7 (1894), table op. p. b^i. 



2 Graptolite-bearing Rocks of Victoria. Geol. Mag. (n.s.), Dec. iv., vol. vi. (1890), pp. 442-143 



3 Geol. of Castlemaine. Proc. Roy. Soc. Victoria, vol. vii. (n.s.), 1894, p. 88. 



4 Graptolite-beariiij; Rocks, op. cit., i>. 443. 



5 Vide p. 55. 



