502 



ME. E. E. L. DIXON AND DR. A. VAUGHAN ON [Nov. I9II 



Eastern Gower. The subzone passes up insensibly into the similar 

 limestones which form the lower part of S . 



In the Caninia Oolite, it may be observed in passing, there are 

 thick bands of fine-grained, non-oolitic material, some of which 

 is foraminiferal, some comminuted-crinoidal ; corals are more fre- 

 quent near the top of the Oolite than at lower levels, those noticed 

 being Michelinia, Syringopora, and a Clisiophyllid. 



The thicknesses of the subdivisions of Horizon y and C x vary 

 somewhat, as may be seen from the accompanying table. The 

 thickness of C 2 was obtained, with some uncertainty on account of 

 faulting, only between Fall and Mewslade Bay ; it probably lies 

 between 280 and 350 feet. 



Thicknesses in feet of Horizon y and Subzone Oi in 

 South-Western Gower. 





7 



Luminosa Dolomites. 



Caninia Oolite. 



Total, y + Cj. 



Lower 

 part. 



Upper 

 part. 



Total. 



Fall 



120 

 135 



80 

 115 



60 



90 



140 

 205 



160 (at least) 

 130 



420 

 470 



Inner Head... 



The best exposures of Horizon y and C are (1) the Inner Head 

 islet, accessible for a limited time from the mainland by crossing 

 the rocky isthmus at low tide : — the whole, except the top of C 2 ; 

 (2) the cliff-top near Old Castle, Rhossili, where y has yielded the 

 fauna enumerated on p. 545, and the Laminosa Dolomites also are 

 seen ; (3) Tears Point and the cove called ' Fall ' on the north : — 

 y and C l ; (4) the fine range of cliffs l between Fall and the bluff 

 west of Overton Mere : — C 2 with much of S. 



Seminula Zone, 2 S. — This zone has almost the same facies as 

 in the Eastern District. The top appears, however, to be so lacking 

 in rock-types characteristic of Modiola phases, that it is separated 

 from the rest of S 2 , not on its own merits, but for purposes of 

 comparison with the Modiola phase on this horizon in other areas. 



The general sequence, which has been determined more exactly 

 than in Eastern Gower, is as follows, in descending order : — 



3. Modiola phase. Evidenced merely by occasional ' pisolites.' 

 The ' pisoliths ' outwardly resemble those which are so abundant in 

 the Eastern District, but include fragments of a Mitcheldeania-like 

 alga. True calcite-mudstones, such as ' chinastone-limestones,' if 



1 Described by Dr. A. Strahan in the West Gower Memoir, pp. 12-13. 

 First recognized m this district bv Dr. G-ubbin & Dr. Vaughan, Proc. 

 Bristol Nat. Soc. ser. 4, vol. i (1905) pp.' 44-50, 54-56. 



