570 ME. J. A. DOUGLAS ON THE [Kov. 1909, 



TIL SUMMAEJ OF CONCLUSIONS. 



The total thickness of Carboniferous Limestone in County Clare 

 amounts to about 3250 feet, and the zonal sequence of the con- 

 tained fauna is found to be essentially similar to that of other 

 British areas, and to admit of more or less accurate correlation. 



The Lower Limestone is found to contain a Tournaisian fauna, the 

 Upper a Visean, the distinction between the two being well marked. 



The Old Red Sandstone is succeeded in apparent conformability by 

 a bed of sandstone containing abundant modioliformlamellibranchs. 



The Cleistopora Zone is poorly represented by a few feet of sandy 

 shales at the base of the sequence. 



To the Zaphrentis Zone is assigned the whole of the so-called 

 Lower Limestone Shales and bedded cherty limestones. 



The faunal characters of the clatliratus and JconincJci subzones are 

 well marked, and the succession of the fauna is very similar to 

 that of the South-Western Province of Great Britain. 



Between the uppermost beds of the Zaphrentis Zone and the base 

 of the Yisean occurs a considerable thickness of massive unbedded 

 limestone, which is remarkable for its luxuriant molluscan fauna, 

 especially large cephalopods. The peculiar nature and the faunal 

 contents of this rock suggest the incoming of shallow-water con- 

 ditions, and thus afford evidence of the extension westwards of that 

 general elevation which is indicated by the deposits of the Bristol 

 area, the volcanic rocks of Weston-super-Mare, and the Pendine 

 and Rush Conglomerates. 



Syringothyris cuspidata here attains the acme of its develop- 

 ment, and the beds are assigned to the Syringothyris Zone. A 

 comparison is made between this part of the sequence and the 

 Waulsortian Phase of Belgium. 



The Vise'an is marked by the incoming of a perfectly distinct 

 fauna, including the Clisiophyllids and Lithostrotion, and by a 

 notable change in the nature of the rock : at least one horizon of 

 oolitic limestone occurs in the Seminula Zone. This portion of the 

 sequence is poorly fossiliferous, and the subzones are not well 

 marked. Productus cora mut. S , however, occurs abundantly near 

 the summit. 



The Dibunophyllum Zone attains a thickness equal to that of the 

 Midland development, and is composed of limestone from base to 

 summit. The D 1 subzone is characterized by the abundance of 

 simple Bihunofhylla ; the D subzone by the occurrence of Lonsdalia 

 and Cyathophyllum regium ; and D 3 by the abundance of Densi- 

 phylloid Zaphrentids and Caninia, and by the apparent absence of 

 Clisiophyllids and Lithostrotion. 



Fossils characteristic of the lowest Pendleside Beds have not 

 been recorded from County Clare ; but it has been shown by 

 Dr. Wheelton Hind * that the so-called ' Coal Measure Shales ' 

 which immediately succeed the limestone are the homotaxial equi- 

 valents of some part of that series. 



1 See Bibliographical List, § IX, p. 582. 



