1865.] TAWNEY RH^TIC BEDS AND SUTTON STONE. 77 



8. The position of the Sutton Stone. — Having been struck by the 

 presence of Plicatula intusstriata in the Sutton stone, a shell ac- 

 knowledged to be characteristic of the Ehsetic series, and never, I 

 believe, really found out of it*, I convinced myself by diligent 

 search that the usual Liassic species of Ammonites, &c., were ab- 

 sent from these beds, while those fossils that were present had many 

 of them either been noticed in the Ehaetic beds of the Continent or 

 showed strong affinities to the Upper Triassic fauna. This part of 

 the series was therefore no longer to be considered Liassic. 



It now became necessary to find the boundary between the 

 Ehsetic and Liassic series. By examining the range of the charac- 

 teristic species, Ostrea multicostata and Pecten Suttonensis, I observed 

 that they ceased vertically at a line generally marked by litho- 

 logical characters. 



The Southerndown series as here restricted must therefore be 

 taken from the Lias. The sections seen in the valley between Bridgend 

 and Pyle, and through which the South Wales Eailway runs, are 

 perfectly conclusive as to the non-Liassic nature of the white or 

 Sutton series. 



Near Cwrt-y- Coleman, &c., we find 7 feet of white shelly lime- 

 stones covered by 4 feet of mottled green and yellow marls, and 

 2 feet of purple-red marls. In the Sutton limestone here, Myo- 

 phoria postera is found with Turritella and other shells, of which 

 I have only bad specimens. The marls are Rhaetic, and are very 

 similar to those noticed near Pyle church ; they may be, perhaps, 

 the same as occur at the base of the " Stormy Lime and Cement 

 Works," on the South Wales Railway. 



At the base of these works are 9 feet of dark and pale-green marls ; 

 above are the Avicula-contorta shales (1-i- feet), with Pecten Valo- 

 niensis, &c. ; above this are pale-grey, smooth limestones, sepa- 

 rated iDy dark brown-grey shales, which are the equivalents of the 

 White Lias of the West of England. The fossils here are fish- 

 scales and the following shells : — 



Monotis decussata, I Plicatula intusstriata, 



Modiola minima, | Ostrea liassica, 



and a Gardinia, which also occurs in the White Lias of Saltford. 



Above are argillaceous limestones, with Ostrea liassica and Mo- 

 diola minima. The Ostrea-series is well developed in the neigh- 

 bourhood. 



Another interesting section is seen half a mile north of the last, 

 at French Quarry. The Rhaetic series here consists of white shelly 

 limestones and green marly bands. Monotis decussata and Axinus 

 cloacinus are very abundant; and Ostrea liassica is seen to begin 

 here in the Rhsetic beds, and gradually increase in numbers until 

 it reaches its climax in the '' Ostrea-beds " (Lower Lias). 



Again, in Laleston- churchyard Quarry part of the Sutton lime- 



^ I ha^e lately heard that Plicatula iritusstriata has been found attached to 

 GryphcBa incurva from the Ammonites-Bucklandi beds. I have net, however, seen 

 the specimen. 



