﻿456 



DE. A. VATJGHAIS" ON THE FAITNAL SUCCESSION [Aug. 1908. 



SpecimeDS from Dg of the Eush-Skerries sequence and from D3 

 of Bradbourne (Derbyshire) exhibit the following characters : — 

 Corallites narrow, with very thin walls. Calicos very numerous 

 and unequal (average width = 4-5 millimetres). 



The internal structure 



Pig. 15. — Michelinia tenuisepta(P7z?'Z- consists mainly of flat 



lijos): enlarged vieiu of calic€s{x 2), tabulae which, in the nar- 



from the Cyathaxonia-5^c?s (Dsj) of row portions of the tubes, 



RusJi, E 22. stretch completely across ; 



concurrently with increase 

 of diameter, a lining of loose 

 vesicles makes its appear- 

 ance at the wall. 



The striking characters 

 are the thin walls and 

 the interposition of small 

 calices. 



Occurrence. — This spe- 

 cies is very abundant in 

 D35, and a specimen from 

 the megastoma-Beds is in- 

 distinguishable. The Holm- 

 patrick form seems also to 

 agree in all essential points, but has only been examined in the 

 field. The species is very abundant at Bradbourne. and occurs 

 rarely in ^2—3 of Gower. 



MiCHELINIA TENUISEPTA, Var. EAVOSITOIDES, UOV. (PI. XLIX, 

 fig. 11.) 



This form is homosomorj)hic with Favosites, but differs in the 

 following points: — (1) The majority of the tabulae, although 

 stretching completely across, are seldom continuously horizontal ; 

 (2) The tabulae are frequently replaced by broad vesicles ; (3) The 

 mural pores are large and scattered. 



On the other hand, the relationship of the form to M. tenuisepta 

 is obvious, the differences being entirely dependent on the 

 narrowness of the corallites. 



Occurrence. — This variety is common in, and characteristic of, 

 the lower part of P ; it immediately succeeds the maximum of the 

 typical form of Miclielinia tenuisepta. It is equally abundant in 

 Dg at Bradbourne (Derbyshire). 



Zaphrentis and Densiphyllum. 

 Zaphrentis Enniskilleni, Ed. & H. (PI. XLIX, fi^ 



13.) 



Z. EnniiihiUeni, Edwards & Haime 'Monogr. Brit. Foss, Cor.' pt. iii, p.'_170 



& pl. xxxiv, fig. 1. 

 Prox, Z. Enniskilleni & Z. patula,^ Thotnson & Nicholson, Ann. & Mag. 



Nat. Hist. ser. 4, vol. xvi (1875) p. 428 & pl. xii, figs. 6-6. 



Non Caninia patida, Mich. 



