172 THE GEOLOGICAL AGE OF CENTRAL AND WEST CORNWALL. 



12. Pleurodicf.yum lyrohhmaticum f Goldffj r. FJiiUip^, Pal. Foss., 



2)1. x)x, Jiff. 24. — Looe, Polruan and St. Veep ; Peach 

 'Irnns. R.G.S.C. ix. 52. According to Murcliison it is 

 Middle Devonian, and it occurs in the Plj'mouth lime- 

 stone. F. Eoemer gives it also as a Lower Devonian 

 form. Specimens in Mus. Roy. Geol Soc, Cornwall, 

 and in Mus. Pract. Geol., Lond. 



13. Cdimopora ramosa (Lonsd.J — Stromatopore ramosa {McCoy') v. 



Phillips, Pal. Foss., pi. viii,fig. 22. — Polruan, Fowey, 

 Looe; Peach 1844, Couch 1846. This species occurs 

 also in the Eifel. 



" The Cor7iisli specimens of tbis species are not perfect, and hence their 

 character could not be determined except by a comparison with others. While 

 examining them it seemed to me doubtful whether they could be referred to the 

 jjohjpiaria ; this may have arisen from the imperfect state in which I have seen 

 them ; but they seemed more nearly allied to the sponge, and to the genus 

 Grantia of Fleming." — [Couch, loc. cit.) 



Out of the above 13 species of Corals, 3, viz. Pleurodieti/um 

 problemaiicum, Amplexus tortuosus, and Caunopora ramosa, so far as 

 is known, occur outside the Fowey beds only in rocks recognised 

 as Devonian. Four more — Cystipliyllum Siluriense, Cyathopyllum 

 Elongata, Favosites Cristata, Alveolites Lalechei — are exclusively 

 Silurian. Three more — Favosites fibrosa, F. Gotlilandica, Cya- 

 thophyllum celticum — though Devonian are also Silurian ; while 

 the remaining two — Cyatliopli pauciradialis and C. pluriradialis — 

 being of purely local occurrence are of no value in settling 

 the disputed point of age. It will be noticed that of the 

 common TFew/oc^ corals we find just those which in other districts 

 occur also in Devonian rocks, while of the Devonian corals we 

 have those which pass down. 



POLYZOA. 



1. Fenestella arthritica. Polruan, Couch 1846, and Fowey, 

 McCoy. All localities are in Devon except these only. 



Fenestella arthritica. The only Cornish specimen of this species that I have 

 seen was from Polruan. It was much injured, but belonged to var. a of Phillips. 

 Its surface was rough ; the cells large, regular, with hexagonal openings. The 

 divisions of the cells were occupied with a brown powder, the cavity bj' the texture 

 of the stone, so that it looked like a brown reticulated leaf. — Couch, Trans. 

 R.G.iS.C, 1846, VI., p. 276. 



