564 MR. J. A. DOUGLAS ON THE [Nov. I909, 



VI. Correlation 1 of the Succession in Count? Clare with that 

 of other Districts in the British Isles. 



The Modiola Phase. 



The lamellibranchs found in these beds cannot, in the present 

 state of our knowledge, he definitely correlated with those occurring 

 at the base in other districts. In this district they are not 

 associated with a brachiopod fauna, and consequently the beds are 

 strongly marked off from those of the succeeding zone. Their chief 

 interest lies in the suggestion which they afford of a conformable 

 transition from the Old Red Sandstone. (I have retained the term 

 ' Modiola Phase ' to preserve uniformity with former papers on the 

 Carboniferous sequence.) 



The Cleistopora Zone. 



The sandy basement-beds assigned to this zone exhibit an incom- 

 plete development of the fauna characteristic of the Cleistopora 

 Zone in the South-Western Province (Bristol area and the Mendips). 

 The correlation is based on the simultaneous occurrence of a bassi- 

 form Productus and Spiriferina octoplicata ; on the presence of 

 Eumetria aff. carhonaria, GamarotcecJiia mitcheldeanensis, and Ortlio- 

 tetes crenlstria in a mutation similar to that found in K x of the 

 Avon section ; and on the complete absence of Zaphrentis, which 

 occurs in great abundance in the overlying beds. 



The absence or great rarity of Spirifer aff. clathratus, Rhipido- 

 mella micJielini, Productus cf. burlingtonensis, and Sy ring othy vis aff. 

 cuspidata, from beds immediately below those containing Zaphrentis, 

 enables a more marked divisional line to be drawn between this 

 and the succeeding zone than in the South-Western Province, and 

 suggests a relative acceleration of the coral-fauna on the brachiopod- 

 fauna at the base of the sequence. 



The extreme thinness of this zone has been mentioned above. 



1 Since the publication of Dr. Vaughan's paper on the Bristol area, much 

 detailed work has been done on Carboniferous paleontology. I have adhered 

 for the most part to the original names given in that paper, for the purpose of 

 avoiding confusion in correlation. The following changes bave, however, been 

 inserted (taken from the work of Mr. R. Gr. Carruthers on certain Tournaisian 

 corals, Geol. Mag. dec. 5, vol. v, 1908, pp. 25, 67, & 159) :— 



Zaphrentis omaliusi — Z. aff. phillipsi (pars). (Bristol paper.) 

 Zaphrentis JconincM = Z. cornucopia. (Bristol paper.) 

 Caninia cornucopia — Amplexi-Zaphr cutis. (Rush paper.) 



