1866.] DUNCAN — INFEA-LIAS CORALS OF SOUTH WALES. 23 



Ammonites angidatus in the east of France, and the Calcaire de 

 Yalogne, besides representatiye and allied species. It will have 

 been noticed that the corals whose species are identical or common 

 are accompanied in all these series by the same sj)ecies of Gastero- 

 poda and Biyalves. There is therefore a great general similarity of 

 arrangement. 



7. The geological ])osition of tlie Brocastle, Eivenny, Sutton, and 

 SoutJierndoiun series. — The similarity of arrangement noticed above 

 justifies the correlation of the Brocastle conglomerate, the Ewenny 

 Limestone, and the Southerndown and Sutton series with the Calcaire 

 de Yalogne, the Foie de Yean, or the zone of Ammonites Moreanus, 

 and the Gres calcareux. It is well known that these continental 

 beds form the upper part of the Infra-Lias. Since the strata just 

 mentioned are superimposed on the equivalents of the Ammonites- 

 planorlis zone of England, the Welsh fossiliferous beds resting on 

 Mountain -limestone must be higher in the geological scale than this 

 zone. Situated, then, without any direct stratigraphical relation 

 with any member of the Ammonites-planorhis zone, the Sutton, 

 Southerndown, and Brocastle beds form part of one province, and 

 are the representatives and equivalents, lithologically and palaeonto- 

 logically, and in a positive as weU as in a differential sense, of the 

 beds included in the zones of Ammonites angidatus and A. Moreanus 

 — the Hettangian. 



Dr. Wright* remarks upon the imperfection of the zone of Ammo^ 

 nites angidatus in England as foUows : — '^ The zone of Ammonites 

 angidatus, so far as it has been exposed, appears to be im^Dcrfectly 

 developed in the British Isles ; and from the difficulty experienced in 

 separating its beds from the Bucklandi-series, they are grouped with 

 the latter in my memoir." He proceeds, " This zone was well 

 exposed in the Harbury cutting near Warwick, although very few 

 Mollusca besides Ammonites angidatus were obtained." He notices 

 the zone in Yorkshire, Gloucestershire, and in the north of Ire- 

 land. 



The following scheme of the succession of strata in Great Britain 

 between ih.Q Ammonites-BucJdandi zone, or the true Lower Lias, and 

 the Keuper is probably consistent with truth : — 

 Lower Lias. — A. BucJdandi, A. Conyhcarii, Gri/phcBCC incurva (type). 



/^Fossiliferous dolomitic limestones with a large fauna of 

 Upper zone, 'i Madreporaria, Grasteropoda, and Lamellibrancliiata, 



J — Brocastle, &c., SoutherndoTrn (Sutton). 



I Astrocrenia-beds = zone of A. Moreanus and the Calcaire 



I de Yalogne, &c. lAnc.6bisi'n.ve\)edis>,zonQoi A. angidatus 



y (Wright). 



f A.-]planorbts zone (Wright). 



^r■^l^^ Septasfr(sa Hai7nei = zouQ of A. Burqundice of the Cote 



Middle zone. 1 I'r). 



{_ Y^'hite Lias in part. 



{Wliite Lias in part. 

 Avicida-conforta beds, |-Eha;tic (Moore.) 



Marls abore the Keuper (Dawkins) 

 Keuper. 



* Mon. Pah Soc. for 18G3. 





