During Triassic and Jurassic Periods 187 



Selachii. Sphenacantlius or ?. 



Dipnoi. Gosfordia, a genus allied to but distinct from Con- 



chopoma of Permian rocks, from Ctenodus of Palaeozoic 



rocks, and Ceratodus of Mesozoic age. 

 Ganoidei. Myriolepis cla'rkei; M. latus, allied to the South 



African Atherstonia. 



Apateolepis australis, related to the Carboniferous genera 

 Plianerosteon and Actinophorus. 



Dictyopyge illustrans, D. robusta, and D. symmetrica. 



Belonorhynclitis gigas and B. gracilis. 



Semionotus australis and S. tenuis. 



Pristisomus gracilis, P. latus, and P. crassus. 



Cleithrolepis granulatus and C ? latus. 



Pholidophorus ? gregarius. 



Peltopleurus ? dubius. 



After an elaborate analysis and comparison with other 

 fish faunas he concludes: "So far as can be determined 

 from the fishes therefore, the Hawkesbury beds may be 

 regarded as homotaxial with the Keuper of Europe, or at 

 least with the Rhaetic, and on the whole the writer is 

 inclined to adopt the first of these interpretations." The 

 above list however suggests a curious admixture, of genera 

 peculiar to the strata such as Gosfordia, Myriolepis, 

 Apateolepis ; of others like Cleithrolepis that are common 

 to South Africa and Australia; and still others like Dictyo- 

 pyge, Semionotus and Pholidophorus that stretch across 

 the continents. 



But that over the present area, a degree of separation 

 in time or space, may give rise to a very different fauna. 

 Is proved by the St. Peters list. This includes amongst 

 selachians Pleuracanthus parvidens ; amongst Dipnoi, Sage- 

 nodus laticeps; amongst Actlnopterygll Palaeoniscus crassus 

 and P. antipodeus, Elonichthys armatus, E. semilineatus, 

 Myriolepis pectinata, Elipsopholis dunstanii, Semionotus 

 formosus and Pholidophorus australis. Commenting on 

 the above Woodward Inclines to regard the group as of 

 Carbo-Permian affinity. But the presence of such typically 

 upper Triassic or Liassic genera as Semionotus and 

 Pholidophorus along with Palaeoniscus, would suggest 

 rather that this Australian area was a combining centre or 

 mixing place for older and newer elements derived from 

 other regions. 



But In connection with our present fundamental con- 

 tention, Woodward's observations on the Dipnoi are most 



