nt K. J. TILLYARt). 725 



actual difference in geological time between the Belmont fossils 

 and those from the top of the Dirty Seam at Newcastle. These 

 latter, even if nothing is allowed for the break, lie some 250 feet 

 below the horizon of the Belmont Beds. They are, therefore, 

 by far the oldest, fossil insect-wings so far discovered in 

 Australia. 



The Upper Coal-Measures, in which the insects are found, are 

 generally classed in text-books as Permo-Carboniferous. This 

 name, first suggested by Mr. R. Etheridge, Junr., is applied to 

 the immense series of marine and freshwater beds, totalling a 

 maximum thickness of about 17,000 feet, which overlie the true 

 Carboniferous Beds in New South Wales, and are, in turn, fol- 

 lowed by the freshwater Triassic strata. The marine beds con- 

 tain a fauna which shows afiinities with both Carboniferous and 

 Permian marine faunas of the Northern Hemisphere. The name 

 Permo-Carboniferous is an attempt to emphasise this fact. 

 When, however, we come to apply the term to the freshwater 

 beds of the Upper Coal-Measures, we are met with the difiiculty 

 that this Permo-Carboniferous affinity with the Northern Hemi- 

 sphere faunas does not exist in this case, since the flora displays 

 a more decidedly Mesozoic aspect, and does not possess a single 

 one of the Carboniferous genera. The Calamiies, Lejndoden- 

 dron, and Rhacopteris of the Carboniferous have disappeared; 

 and, in their places, we find Fhyllotheca, Schizotieiwa, Alethopte- 

 7'is, SpheuojJteris, 'dnd Baiera, all represented also in the Triassic, 

 together with an abundant Glossopteris-hora (which is typical of 

 the Permo-Carboniferous only), Auiiularia, Ganyaniopteris, Ver- 

 tebraria, Dadoxyloii^ and other genera not found in the Trias. 

 Thus, as far as the flora is concerned, it would be more logical 

 to coin the term Triasso-Perraian for it, than to retain the term 

 Permo-Carboniferous. As the Insects studied in this paper have 

 nothing in common with any known Carboniferous fauna, but 

 show distinct affinity with the Triassic forms already brought to 

 light, I think that I should be open to the charge of misleading 

 students of Palseo-entomology in other parts of the world if I 

 classed them as Permo-Carboniferous. The term Permian is less 

 open to objection, and I have adopted it in this paper. As all the 



