Yd. 67.] THE CARBONIFEROUS SUCCESSION IN GOWER 547 



Gasteropods : — 

 Large species of Bellerophon and Euomphalus are abundant. 



Cephalopods : — 



A large species of an Orthocerate is common. 



Seminula Zone (S). 

 S,: 



Eastern District: Threecliff Bay (4) and the cliff-section 

 from Longland to Mumbles. 



South-Western District: Overton (denoted by 2). 



Corals: — 



Michelinia grandis (M'Coy) — 2. 



Caninia (Cyathophylloid) bristolensis L Vaugban — 2, 4 and 6. 



Cyathophyllum <p Vaugban — 2 and 6. 



Lithostrotion cf. irregulars (Phill.) Ed. & H. — 4, 6 (only at tbe base). 2 



Lithostrotion martini Ed. & H., and variants — 2, 4, 6. 



Dipbypbyllid 3 — (> (only at tbe base). 



Heterophyllia 4 sp. — 2. 



Brachiopods : — 



Productus aff. semireticulatus, mut. S x Vaugban — 2, with fragments of a 



large Prodicctics. 

 Productus cf. elegans M'Coy — 2 (abundant). 



Chonetes cf. comoides (Sow.) — (persists at Overton as long as Caninia). 

 Seminula ficoides Vaugban, and varieties — 2, 6 (very abundant). 



Gasteropods : — 



Bellerophon, Euomphalus, and Loxonema abundant — 2, 6. 



Bryozoa : — 



Fenestellids and Heterotrypa cf. tumida (Phill.) crowd tbe sbaly 

 partings at Overton (2). 



Trilobites : — A Pbillipsid is common— 2. 



[The resemblance of Sj at Overton to S x of the Avon is very 

 striking, for the shaly partings are crowded with the same species 

 of bryozoa enmeshed in a network of spines broken from the 

 index Productus and accompanied by the same small trilobite ; 

 while the limestones themselves contain at both places Caninia 

 bristolensis in abundance.] 



Sj of Gower only differs from S x of Bristol in that, in Gower, 

 Cyatlioyyliyllum persists into S x and Seminula is established later. 



1 Proc. Bristol Nat. Soc. ser. 3, vol. x (1903) p. 103 & pi. i, fig. 4 ; = Caninia 

 cylindrica, mut. Si of ' Bristol Paper.' 



" This species differs from L. irregtdare of tbe D levels in its strikingly 

 ramulose habit. The beds in which it occurs have a typical C-S fauna, and 

 were formerly considered by me to mark the top of C 2 ; it is somewhat more 

 convenient to consider them as the base of S r In any case, C 2 and S x are 

 faunally continuous both in (2) and (6). 



3 Diphyphylloid Lithostrotions are not uncommon in C-S, and again 

 are very common in Upper D, but are apparently absent from S proper, where 

 Lithostrotion reaches its maximum. 



4 Collected by the late Dr. W. B. Gubbin (Bristol Nat. Soc. op. jam cit.). 



