BT W. K. BENSON, W. S. UUX, AND W. R. BROWNE. 369 



Sfiirifera hisuicata C2 to D-j 



andM.G. (Id?) 



duphcoftata Di t(i D2 



mosquenxh var* D2 (l.C.) 



pinguis Ci td Ta 



striata] Ci to D2 



Spiriferiiia >i:sci(lpl'<i ('i to D2 



Actiiiocoiichwi phduisiilcdtux Ri to D2 



Perhaps the best manner to obtain an approximate idea of the average horizon 

 of such a fauna is to accord numerical values to the zones from Ki {= 1) to D2 

 (=10), and obtain thus the arithmetical average position of the Burindi fauna by 

 comparison with the modern British work. It is then found that the Burindi 

 fauna centres in the Si (the Lower Semirmla) zone, near the base of the Visean. 

 If, however, we consider also the older Scottish records and place a value of 12 

 on the Millstone Grit, and 14 on a form rising higher than this we find the same 

 result. « Comparing this with our Australian faunae we may note that the fact 

 tliat Bhynchonella pleurodon descends into the Upper Devonian may be balanced 

 against the ascent of Dielasma saeculum var. hastata, and var. ami/gdala to the 

 higher parts of the Upper Marine Permo-Carbouiferous Series. 



Quite in accordance with this conclusion we may note that Michehnia temii- 

 septa which occurs in our region, ranges in Great Britain from Z2 to Di,and that 

 Seminula subtilita, though it occurs in the Tournaisian of Belgium and its equiva- 

 lent in America, and is sometimes in the equivalent of the Visean Beds; it is 

 chiefly found in the Upper Carboniferous Formations of that continent. More- 

 over, there appears at several localities in Great Britain, in the Middle of the 

 Lower Carboniferous Beds (C and S zones), a great influx of species of gastro- 

 pods, particularly Eiiomphalus, Bellerophon, Lo-conema, Straparolhis and Nati- 

 copsis, genera also well represented in the Burindi fauna. It is questionable, 

 however, whether this is a factor of correlative ^alue, being possibly indueiu'cd by 

 the general shallowing of the British province at this epoch. 



A wider study of the Burindi fauna shows a somewhat similar result. In a 

 later part of this series of papers the writer hopes to give a complete census of 

 the Burindi fauna as far as is known for the legion extending from Port Ste- 

 phens to the Gwydir River near Moree (Graveseud). We may. liowevi r. antici- 

 pate this by stating the results of study of the ranges, so far as the writer can 

 ascertain them, in tlie British Isles of the remaining brachiopods that also occur 

 in the Burindi fauna in New South Wales. The following are stated in the 

 same way as before: — 



Orblculoidea r.ithla Ci U.C.M.|| 



Leptaena analor/a Ki to D2 



Chovetes la<piefsiaiia Ki to Z2 



papiUonacea (and varieties) Zi to Si 



•According to Freeh this passes into the Upper Carboniferous. 



fPasses into the Upper Carboniferous in Russia. 



§In this 'calculation it is assumed that all forms recorded from the Calciferous Sand- 

 stone extend as low as Kl. If, as may well be the case, this assumption is not strictly 

 true, the average Burindi horizon would then be somewhat higher than indicated above. 



IIU.C.M. Upper Coal Measures. 



