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 Crinoidea 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 Eifel lime- 
stone*. Two of them are also met with in the carboniferous 
limestone of Liege and Namur, namely, Cyathophyllum ccEspi- 
tosum, Cyathophyllum pentagonum ; and one in the lower part 
of the coal formation of Liege, namely, Cyathophyllum quadrd- 
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 Terebratula con- 
Centrica, some Spiriferce and Euomphali, besides Productce 
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 lim.estone ? 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, Terebratula aspera, and T. Wilsonii, 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 bond, and Edinb. Phil. Mag. for August 1839. 
