﻿Vol. 64.] THE FOSSILIFEROUS SILURIAN EOCKS OF TORTWOETH. Q4:& 



of the prolongation, beneath the surface, of such a buttress in a 

 southerly direction. 



He also congratulated the Authors upon having made a valuable 

 addition to our knowledge of the Palaeozoic geology of this part of 

 England. 



Prof. Eeynolds briefly replied, saying, in answer to Dr. Cullis, 

 that the Authors were fully prepared to accept his suggestion with 

 regard to the derivation of the celestine. 



Mr. Reed commented on the absence of any palaeontological 

 evidence of the occurrence of Lower Llandovery beds. The Upper 

 Llandovery of the district was characterized by the presence of 

 certain species peculiar to the locality or rare elsewhere (as, for 

 example, Phacops Weaveri, Coelospira hemispherical etc.), and the 

 non-occurrence or rarity of some typical forms, such as Pentameriis 

 ohlongus. A certain admixture of Wenlock species was probably 

 connected with the calcareous nature of some of the beds. The 

 Wenlock Series accordingly showed no such hard-and-fast line 

 of division palaeontologically from the Llandovery as usual. The 

 rarity of recognizable crinoids and massive corals, the want of 

 variety in the trilo bites, and the occurrence of certain local peculiar 

 species (such as Orthis hasalis) were noticeable features. The 

 Ludlow formation was undoubtedly present in the area, as proved 

 by the discovery of Aviculopecten Danhyi, Anodontopsis securiformis, 

 etc., but fossils were scarce in it. 



