﻿198 DR. A. VAUGHAN ON THE PAI^EONTOLOGICAL [May 1905. 



Productus aff. Cora, mutations. 

 Producing giganteus. 

 Productus hemisphericus & vars. 

 Chonetes aff. comoides. 



Brachiopod-fauna: 



(?) Bielasma kastata. 

 Seminula ficoidea and allied 



forms. 

 Orthotetes crenistria, mut. D. 



Subdivisions : — 



D x = Subzone of Dibunqphyllum 6 and Bibunophyllum <j> 



(#(/>-subzone) . 

 Where exposed in the Avon section : — 

 Clifton side : 



Of the exposures already mentioned as included in the whole 



zone, those up to a little beyond Point Villa before the fault, and 



the whole of the exposure mentioned after the fault, belong to 



this subzone. 



Note. — Fossils labelled 'Point,' ' Hotwell House,' 'Boiler-Bed,' and 



1 Behind the Colonnade,' etc. are derived from beds in this subzone. 



Leigh Woods side : 



The beds near the Point on that side of the river. 



Special fauna! characters : — 

 Brachiopods : 



Productus ' giganteus ' x abounds towards the base, and the 

 thick-shelled Chonetes aff. comoides is not rare. 



Productus aff. Cora occurs in a well-marked mutation. 



Pr. hemisphericus is abundant just above the rich coral-band. 



Seminula ficoidea is uncommon and Orthotetes rare. 



Corals : 



Cyathophyllum Murchisoni teems in several well-marked 

 varieties, between which there are complete transitions. 



Clisiophyllids belonging to both the Clisiophyllum- and Dibuno- 

 phyllum-sections reach their maximum, the most abundant forms 

 being cylindrical or elongate members of the group of Dibuno- 

 phyllum aff. turbinatum, which are here designated D. and D. 0. 



Syringopora and Alveolites are both abundant (the commonest 

 species of Syringopora being S. cf. distans and JS. cf. geniculata). 



Campophyllum aff. Murchisoni reaches its maximum. 



A Koninckophyllid Cyathophyllum occurs rarely. 



Lithostrotion Martini and its mutations are not uncommon, but 

 are far less abundant than in the zone below. 



Lithostrotion irregidare becomes important. 



Lithostrotion junceum occurs, but is never abundant. 



In the Avon section this subzone is chiefly recognized by the 

 enormous abundance of simple Cyathophylla and of elongate 

 Dibunophylla, both of which groups reach their maxima. 



1 Productus 'giganteus'' merely implies large, convex Producti, with close 

 and flexuous, longitudiual ribbing and broad, over-rolled beak. It is a con- 

 venient field-term, but I am ignorant of the hinge-characters. 



