330 ME. T. P. STBLY ON THE CAKBONIFEEOUS [May I906, 



Amplexus cf. coralloides, which is apparently confined to this 

 subzone, occurs very commonly when at a maximum. 



Michelinia cf. favosa attains a second maximum in the lower part 

 of this subzone, where it is prolific ; but afterwards declines rapidly, 

 and does not range above Horizon y. M. cf. tenuisepta probably 

 occurs in this subzone. 1 



Syringopora 6 is characteristic, and very common at certain 

 levels. S. cf. reticulata first occurs at Horizon y. 



Cyaihophyllum 6 occurs in this subzone. 



Brachiopods : 



Spirifer aff. clathratus and var., though greatly diminished in 

 numbers, persist abundantly throughout the subzone. Sp. cf . cinctus 

 occurs not uncommonly. 



Syringoihyris aff. laminosa attains its maximum. S. aff. cuspidata > 

 mut. C, enters, and increases in abundance towards the top. 



Ortkothetes aff. crenistria (especially in the mut. Z), is extremely 

 abundant throughout. 



Leptcena analog a attains a second maximum, and occurs commonly 

 up to Horizon y. 



Athyris cf. glabristria, mut. Z , is abundant, and Reticularia cf. 

 reticidata occurs commonly ; but Athyris Royssii is very rare. 



jRhipidomella aff. Miclielini occurs commonly throughout. 

 Schizophoria aff. resupinata enters, and can be found occasionally 

 throughout the subzone, but is never abundant below Horizon y. 



Productus cf. Martini is not uncommon. Pr. cf. semireticulatus 

 occurs sparingly below Horizon y, but is not uncommon at that level. 

 Pr. aff. pustulosus ranges throughout ; the most typical form occurs 

 commonly at Horizon y. 



Chonetes cf. hardrensis is much diminished in numbers, but is 

 still abundant at recurring levels throughout. Ch. cf . papilionacea 

 gradually increases in numbers, and is abundant at Horizon y. 



Martinia cf. linguifera* Pugnaoc cf. pugnus, 2 and Productus cf. 

 aculeatus occur very rarely in this subzone. 



y = Horizon y. 



This includes the uppermost part of the zone, and exhibits an 

 overlap of the Zaphrentis- and Syringothyris-iauuas. The out- 

 standing palaeontological feature of this horizon is the 

 extreme abundance of Caninia cylindrical, mut. y. 



Horizon y must be regarded as the top of the Zap>hrentis-Zone, 



1 The specimen of Michelinia temcisepta figured by Edwards & Haime, 

 ' Monogr. Brit. Foss. Corals ' (Paleeont. Soc.) pt. iii (1852) pi. xliv, fig. 1, and 

 preserved in the Bristol Museum, was obtained from the Mendips. near 

 Maesbury. 



2 Identical forms occur at the same horizon in the Carboniferous Limestone 

 of Freshwater West, near Pembroke (South Wales). I have had the oppor- 

 tunity of comparing the specimens from this locality, collected by Mr. A. L. 

 Leach, of Tenby, with my own specimens. 



