Vol. 67.] THE AVOMAN OF BURRINGTON COMBK. 367 



Brachiopods : — 



Productus pustulosus Phillips, mut. C ; large form. Common at one 



level. 

 Productus cf. semiretimlatus (Martin) : the Waulsortian form. 

 Papilionaceous Chonetes. 

 Chonetes cf. comoidcs (Sow.) : Productoicl and Laptsenoid groups, the 



Productoid group predominating. Abundant at a certain level. 

 Orthis reswpinata (Martin) : the typical form. Abundant at one level. 

 Spirifer sp. : a Waulsortian form. Rare. 

 Syringothyris aff. cuspidata (Martin) : the typical large C form. 



Common ; the acme of this species is in the Waulsortian phase of 



this subzone. 



The interest of the foregoing list lies rather in what it suggests, 

 than in the scanty fauna which it actually enumerates. 



In the abundance of large Producii- Chonetes and giant Caninids 

 we can recall the ' Productus-giganteus Beds' and 'serpent-rock' of 

 South Pembrokeshire. 



In the giant brachiopods (Syringothyris cuspidata, etc.), and in 

 the long worm-like Amplexus, we see in very feeble outline the 

 rich Waulsortian knolls of Belgium and Ireland. 



The dividing line between Lower and Upper Avonian in the 

 South- Western Province has, following the suggestion of Mr. E. E. 

 L. Dixon, been shifted from its former position, at the base of S x , 

 to the middle of C ; his argument is based upon the fact, which 

 he has convincingly demonstrated, 1 that this was the period at 

 which emergence gave way to subsidence in the west of the South- 

 western Province. 



Considered from the faunal standpoint, and with our present 

 more complete knowledge, there can be no question that the old 

 system which involved the separation of the top of C from the 

 bottom of S is unworkable, owing to the earlier introduction of 

 Lithostrotions and their kin in the west of the Province. 



The subjoined table (p. 368) presents the faunal ranges, as they 

 are now known, with regard to the two lines Cfj 2 and C. ; S. Mere 

 inspection shows that the upper part of C 2 must be included with 

 S , and that C T must lie below the separating line ; but that it is 

 immaterial from this standpoint where, within the lower part 

 of C 2 , the division between Upper and Lower Avonian is taken. 



The further question of the use of the Belgian terms ' Tournaisian ' 

 and ' Visean' to designate the Lower and Upper divisions of the 

 Avonian, is complicated by the uncertainty of the division-line in 

 the Belgian Province itself. As it seems, however, that the new line 

 of division in the South-Western Province will practically coincide 

 with the division between Tournaisian and Vise'an at the base of 

 the ' Marbre noir de Dinant,' the Belgian names can be usefully 

 retained. 2 



1 'Carboniferous Succession in Grower' Abs. Proc. Gr. S. 1909-10, pp. 72- 

 73. 



2 See H. de Dorlodot, ' Relations entre l'Echelle Stratigraphique du Oalcaire 

 Carbonifere de la Belgique et les Zones Paleontologiques d' Arthur Vaughan, 

 d'apres les Recherches les plus recentes ' Bull. Soc. beige de Geol. vol. xxir 

 (1910) Proc. Verb. pp. 247-90. 



