﻿Vol. 6 1.] SEQUENCE IN THE BRISTOL AREA. 243 



The table and the range-diagrams (which express the same results 

 graphically) are compiled for the Bristol area as a whole, and 

 from the data supplied by that area alone : that is, no account is 

 taken, either of any district outside the Bristol area, or of the 

 smaller variations within the area itself. 



III. Ranges and Maxima op the Corals and Brachiopods in 

 the Bristol Area. (Pis. XXVIII & XXIX.) 



CORALS. 

 Alveolites. 



Species-group: Alveolites septosa. 



Very rare at the top of S x ; commoner in S., ; abundant through- 

 out D ; maximum in D r 



Syringopora. 



Genus : rare in Z l ; abundant at numerous levels throughout all 



the higher zones. 

 Circuli: — 



(1) Syringopora 6 : Z; maximum in Z 2 and y. 



(2) JS. cf. distans : common throughout S and D. 



(3) S. cf . ramulosa : not uncommon in S. 



(4) S. cf. geniculate: maximum in D 7 . 



(5) S. cf. reticulata : maximum in C r 



Michelinia. 



Genus : rare in Z 2 ; maximum at the top of Z, and in C. 



Species-groups (?): not satisfactorily differentiated. 

 The form in Z 5 is Michelinia cf . favosa ; the commonest form in 

 Z 2 and C is M. megastoma. 



Cleistopora. 



Species- group: Cleistopora aff. geometrica. 

 Confined to K ; maximum at the top of K 2 . 

 Zaphrentis. 



Species-groups : — 



(1) Zaphrentis air. Phillipsi. Not infrequent in Z x ; extremely 



abundant in Z 2 and y ; rare in C. 



(2) Zaphrentis aff. cornucopia?. Z 2 and y (abundant); maximum 



at the top of Z 2 ; rare in C r , 



Caninia. 



Species-group : Caninia cylindrica. 



Occasional at the top of Z 2 ; maximum in y ; rare in C ; 2nd 

 maximum in S,. 

 Mutational stages: — 



(a) Caninia cylindrica'. y and C. 



(b) Caninia cylindrica var. bristolensis : C and S x . 



Amplexus. 



Species-group: Amplexus cf. coralloides. 



Z 2 , y, C, and probably S x ; maximum near the top of Z.,. 



