Vol. 67.] THE CARBONIFEROUS SUCCESSION IN GOWEB. 551 



Trilobites : 



The tvpes of GriffiiMdes barkei H. Woodw. (e) (Geol. Mag., 1902, 

 p. 4*84) and Gr. ylaberH. Woodw. (b) (' Mon. Brit. Carb. Tril.' pt. ii, 

 Pal. Boo. 1884. p. 40). 



Note on the Bishopston Fauna. 



The only noticeable differences that distinguish the Bishopston 

 fauna from that of Oystermouth are the absence of Zaphrentids at 

 Bishopston and the predominance there of Spirifer trigonalis (Mart.) 

 over Sp. bisulcatus Sow. The large number of species common 

 to the two localities demonstrates approximate equivalence of 

 level, and also the Upper D age of both faunas. 



Note on the Horizon of the D 2 _ 3 Beds of Gower. 1 

 [Evidence and inference are here set out under localities.] 



(i) Bishopston : — 



(1) The Kottenstones represent the top of the D series ; 



(2) The shales immediately above the Bottenstones, and 



interbedded with the radiolarian cherts, have yielded 

 Posicloaiella Icevis, Solenomorpha minor, and Glyphioceras 

 btlingue — fossils which Dr. "Wheelton Hind identified 

 and considers to indicate a level *' low down in the 

 Pendleside Series." 



It is also important to note that, in shales considerably above 

 the level of those in the Bishopston cutting, Glyphioceras spirale 

 (Phill.) is recorded by the Geological Survey. 2 



(ii) The two quarries on Colts Hill, Oystermouth. — 

 The Southern Quarry is in D x , and there is a continuous series of 

 some 1 20 feet of massive limestone between it and the base of D 2 _ 3 

 in the Northern Quarry. This limestone is very poorly fossiliferous, 

 although it contains a bed crowded with a latissimoid variant of 

 Productus hemisphericus Sow. near the base of the Northern Quarry. 



Allowing a certain weight to this form and to the small thickness 

 of the limestone series between the quarries, it is evident that the 

 base of D, , cannot be of later date than D^ age. 



2-3 2 o 



The fauna of the base of the D 2 _ 3 series in the Colts Hill Quarry 

 cannot be distinguished from that of the Oystermouth Quarry, 

 except for the presence of ' Cyathaxonia' in the first-named locality. 

 This coral occurs with Zaphrentxs nr. oystermoutliensis in the Cya- 

 thaxonia Beds of the Hush and Loughshinny sequence in County 

 Dublin, and I have already suggested (' Loughshinny Paper ' p. 444) 

 that these last-named beds are the equivalent of part of D _ of 

 Gower and of part of D, of the Bristol Area. 



(iii) Port Eynon. — Succeeding the massive and typical D 2 lime- 

 stones at Port Eynon are ihinly-bedded limestones and shales of 



1 See also § II, p. 495. - Swansea Memoir, p. 25. 



