390 Mr. Weaver on the Structure of the South of Ireland, 



tained in the schistose rocks. But the only fossils enumerated 

 hitherto are referred to the genera Producta, Spirifera, Stro- 

 phomena, and the remains of Crmoidea and Polyparia. 

 Where, then, it may be asked, are the peculiar organic re- 

 mains of the Llandeilo and Caradoc formations and of the 

 Wenlock shale, to which this system is referred ? 



In the lower calcareous system, referred to the Wenlock 

 limestone, ten species of coral are enumerated, six of which 

 occur in the Wenlock limestone, and eight in the Eif'el lime- 

 stone*. Two of them are also met with in the carboniferous 

 limestone of Liege and Namur, namely, Cyathophyllum caspi- 

 tosum, Cyathophyllum pentagonum ; and one in the lower part 

 of the coal formation of Liege, namely, Cyathophyllum quadri- 

 geminum. Of Terebratula we have two species common to 

 the Wenlock limestone, namely T. prisca and T, aspera, 

 besides two or three other species not found in the latter. If 

 to these we add Strophomena, Solarium, Nerita, and Crinoidea, 

 we have the whole of the organic remains enumerated as be- 

 longing to this calcareous system in his work on the province 

 of Liege : but at a later period the author remarksf, that in 

 this lower calcareous system are found also Terebratida cou~ 

 centrica, some Spirferce and Euomphali, besides Produdcs 

 and other shells which are commonly met with in the upper 

 calcareous system (namely, the carboniferous limestone). 

 Such being the case, it may be asked, wherein does the ana- 

 logy consist between this lower calcareous system and the 

 Wenlock limestone ? Where are the numerous characteristic 

 fossils of the latter ? On the other hand, the occurrence in 

 this transition limestone of fossils which are common also in 

 the carboniferous limestone, deserves the attention of geolo- 

 gists, since it forms a parallel to similar phasnomena in Devon 

 and Cornwall, and the south of Ireland. 



The upper quartzo-schistous system is referred by M. Du- 

 mont to the Ludlow formation, But where do we find the 

 various fossils of that formation as enumerated by Mr. Mur- 

 chison? The only corresponding species noticed are Spiri- 

 fera radiata, Terebratida aspera, and T. Wihonii. The rest 

 of the fossils given appear more nearly allied to the upper 

 calcareous system (the carboniferous) than to the lower cal- 

 careous (the transition). As bearing on this question, it may 

 also be noticed that in the upper part of this system a bed of 

 coal has been found. 



Of the upper calcareous system there is no question among 



* These will appear in the tables given further on. 

 t See Lond, and Edinb. Phil. Mag. for August 1839. 



