Vol. 67.] THE CAEBONIFEROCS SUCCESSION IN GOWEE. 499 



material is presented both by the valves of gasteropods and by the 

 unrecrystallized part of pseudobreccias. The latter, with typical 

 structure (see PI. XXXVIII, fig. 2) and abundant foraminifera, are 

 as widespread as in the Eastern District, but, like the gasteropod- 

 valves, are in all cases devoid of dolomite. In connexion with 

 pseudobreccias, it may be noted that one of the best exposures 

 of the k pitted ' bedding-planes (p. 490) that characterize some 

 of them may be observed in Tor-gro, Landimore. One such 

 bedding-plane, dipping at a steep angle, which has been described 

 bv Dr. Strahan in the West Gower memoir, p. 12, is shown in 

 PI. XXX VIII, fig. 1. The incoming of Gyrtina septosa (PhilL), 

 which varies in its horizontal distribution, is worth noting ; in this 

 district it first becomes abundant near the base of the pseudo- 

 breccias. 



(2) The D^oolite, which is about 50 feet thick, is coarse-grained, 

 like the baud in the same position in Pembrokeshire. The lowest 

 part is darker, more thinly-bedded and less oolitic than the rest ; 

 otherwise the contrast with the Modiola phase at the top of S 2 , im- 

 mediately below, is complete. 



(3) D 2 has been recognized at Llanrhidian. In the top of the 

 Main Limestone the highest bed exposed in the neighbourhood has 

 yielded the following fauna 1 : — 



Choneti-Productus. Martinia lineata (Mart.). 



Papilionaceous Chonetes or Davie- Productus corrugatus M'Coy. 



siella. Productus edelburgensis-latissimus. 



Martinia glabra (Mart.). | Spirifer bisulcatus Sow. 



The rock is a dark and bituminous, crinoidal limestone, rich in 

 brachiopods ; unfortunately it is seen to a thickness of only a few 

 feet (in low crags 260 yards east of the church). It is underlain 

 by light-grey, nodular limestones, probably pseudobreccias, which 

 have yielded merely giganteid Productus and may belong either 

 to D 1 or to D 2 . Downwards in the sequence other beds are not 

 seen for some distance, and upwards nothing is known until the 

 radiolarian cherts 2 at the base of P are reached: it is uncertain, 

 therefore, whether D 2 _ 3 is present in this district. 



(3) South- Western District. 



The structural features of this district, which lies between 

 Rhossili and Port-Eynon Bays, are shown and described in the 

 Geological Survey map and memoir. 3 Here we need only mention 

 that, owing to a syncline in the promontory south-west of Phossili, 

 much of the sequence Z-C 1 is found along both the north-western 

 and the southern sides of the promontory, and that it is repeated 

 yet again near the Inner Head by an anticline ranging west-north- 

 west through the gut between the mainland and the Worms-Head 

 islets. The western extremity of the Worms-Head islets was not 

 examined. 



1 Identified by Dr. Vaughan and preserved in the Geological Survey 

 Collection (E. D. 891-906). 



- Poorly exposed in a lane a furlong east of the crags of D 2 -limestone. 

 3 One-inch sheet 246 (Worms Head) ; West Gower Memoir, pp. 3, 12-10. 



