﻿224 DR. A. VATTGHAN ON THE PAL2EONTOLOGICAL [May 1905, 



(5) Zaphrentis attains its maximum at, or a little above, 



the maximum of Clioiliyris glabristria. 



(6) CJionetes cf. hardrensis yields its predominance to Chonetes 

 papilionacea from the lower part of the Syringothyris- 

 Zone onwards. 



(7) Syringothyris aff. laminosa enters in the resupinata- 



subzone, and is specially characteristic of the Byringo- 

 tJiyris-Zone. 



(S) Syringothyris cuspidata, in its large and most charac- 

 teristic form, attains a maximum at the top of the 

 resujiinata-suhzone. 



(9) Lithostrotion is, at first, scarce at the base of the Semi- 

 nula-Zone (that is, in the lower part of S x ). 

 (10) Productus 6 is the commonest representative of the genus 

 in the lower part of the Seminula-Zone. 



II. Characters shared by the Sodbury, Avon, and Tytherington 

 sections. 1 



(1) Caninia cylindrica var. bristolensis is characteristic of 



the top of S x . 



(2) Lithostrotion Martini increases from scarcity to extreme 



abundance as we ascend through S x . 



III. Characters shared by the Avon, Failand, and Tytherington 

 sections. 2 

 Cleistopora afF. geometrica attains its maximum in the 

 upper part of the Cleistopora-Zone. 



IV. Characters common to the Sodbury and Tytherington sections. 

 Caninia is scarce or absent immediately above the resu- 

 p)inata-suhzone, and so Horizon y cannot be distin- 

 guished. 



V. Characters common to the Avon and Tytherington sections. 



A Spiriferid of the laminosa-type is characteristic of the 

 top of Sj. 



VI. Characters of especial interest in the Tytherington section. 



(1) Schizophoria resupinata is more frequently met with at 



the top of the clathratus-svibzone than appears to be 

 the case in any of the other sections. 



(2) ZapJirentis and Caninia occur in the ' sub-Oolite ' (com- 



pare a similar occurrence at Pailand and Southmead). 



(3) Chonetes cf. hardrensis is abundant in the lower part of 

 the ' sub-Oolite.' (The species occurs on the same 

 horizon at Failand and Southmead.) 



(4) Rhipidomella aif. Miehelini and Spirifer afF, clathratus 



have been found, though very sparingly, as high up as 

 the bottom of the ' sub-Oolite/ 



1 S x is very incompletely exposed at Failand. 



2 Unobserved at Sodbury, probably on account of the poorness of the 

 exposure. See p. 205. 



