3G8 



GEOLOGY AND PETROLOGY OF THE GliEAT SERPEXTIXE BELT OP X.S.W., 



notation adopted by Dr. \auj;lian has not yet been applied to Australian Geology. 

 In most simplified form we may record it thus: — 



Lower Carboniferous^ — Avonian Series. 



(= Dinantian = Mississippian. ) 



Tournaisian 



X'isean 



Cleistopora 



Zaphrentis 



I _ I 

 Cnninia 



I 

 Dibunophylliuu 



Syringothyris 



Seminula 



I ! I 1 I I i I I 



Lower l^ipi)er Lower Upper Lower Upper Lower Upper Lower Upper 

 Ki K2 Zi Z2 Ci C2 Si S2 Di 1)2 



The division between tlie Tournaisian and the A'isean was i)laced at first 

 between the Syringothyris and Seminula Zones (Si), but now part of the Upju'r 

 Syringothyris Zone, C'l', is inclu<lfd by Vaughan and the Helgian authorities in 

 Ihe Visean (39). 



The braohiopods afford our best grou]) of forms for comparison with British 

 types on account of the better determination. Out of twenty-three species oc- 

 curring in the Somerton. Carroll and Habbinboon region, the following are found 

 in the British Isles, together with the highest and lowest horizon recorded for 

 each in England and Ireland by workers publishing since 1905. In the second 

 column are Davidson's records for Scotland in 1880, referred as far as possible 

 to the new terminology. 



Orthotetes crenistria and varieties Ki to Di; 



and M.G.VS 



Chunetes harArensis Ki to C2 (Da) 



I'ruductus hemisphericus Si to D2 



longispiniii S2 to D2 (Ki?)t 



muricatus , Di (M.G.)^ 



pusiulosun Z2 to Di 



semirctictihili(f:\\ Zi to D2 



(and M.G.*vN) (Ki ' M.G.)§ 



Orthis {Schii<iphori(i) resujiimita Z2 to Di (Ki ?) 



Rhynchonella pleurodoii Di (Ki '?) 



Dielasma hasUittiin Ci to Di (Ki ?) 



sacculum Si 



'See (31), p. 251, but this may be a phase of Di. 



fKi ? ^ Calciferous Sandstone. 



§M.G. = MiUstone Grit. 



il Passes into Upper Carboniferous in Rvissta. 



