552 . ME. J. A. DOUGLAS ON THE [Nov. I909, 



Bryozoa : 



Fenestella multiporata, M'Coy, and other species. 

 Ichthyorachis cf. newenhami, M'Coy. 1 



Special faunal characters: — 



The remarkable and sudden change in the lithological character 

 of these beds is accompanied by the incoming of a perfectly distinct 

 fauna, of which not more than half-a-dozen species pass up from 

 the beds below. The numerous and varied corals of the Zaphrentis 

 Zone have here disappeared, and are replaced by a luxuriant mol- 

 luscan fauna. The abundance of large-sized individuals, both 

 among the mollusca and brachiopoda, seems to indicate a change 

 to relatively shallow-water conditions. The nature of the rock 

 points to rapid deposition 2 ; and the absence of corals, with the 

 exception of Ampleocus, may be possibly thus accounted for ; the 

 essentially tabulate character of this genus suggests the power of 

 rapid growth, which alone would enable it to survive these adverse 

 conditions. 



In this district the rocks are disturbed by minor flexures, and as 

 they are only visible in isolated exposures, it is impossible in the 

 absence of stratification to determine the exact range of individual 

 species throughout the zone ; the faunal assemblage, however, in 

 nearly every exposure was found to be identical. 



The zone is characterized by the great abundance of Amplexus 

 coralloides, which is the only coral recorded. The zonal index, 

 Syringothyris cuspidata, here reaches the acme of its development, 

 attaining an immense size compared with specimens from lower 

 beds. It is never abundant however, and Syringothyris laminosa 

 has not been recorded. Spirifer clathratus is still represented, but 

 in diminished numbers, whereas Spirifer attenuatus, Spirifer pinguis. 

 and Spirifer ovalis are abundant. Spirifer subcinctus is of frequent 

 occurrence. 



Pugnax reniformis, Athyris aff. glahristria, Dielasma hastatum, 

 and Productus semireticidatus are also common. 



Productus aff. quincuncialis and Productus cf. concinnus are 

 widely distributed, but never abundant. 



Schizoplwria resupinata here exhibits its typical characters, but 

 is rare. The other brachiopods mentioned in the faunal list 

 occur sparingly. 



The abundance of mollusca, of which the cephalopod Vestinautilus 

 carinifer is the most prolific, forms one of the distinguishing 

 features of the zone. 



1 The above represents a very incomplete list of the prolific fauna obtainable 

 from this zone, but, I was unfortunate to be working these beds when the 

 quarries had been cleared and most of the material had been broken up as 

 road-metal. Mr. Walsh, the schoolmaster at Cratloe, near Limerick, has 

 however a large collection, and I have to thank him for several of my 

 specimens. 



2 The lamellibranchs, as a rule, preserve their two valves intact, so there 

 cannot have been much transportation. 



