THE 



GEOLOGICAL MAGAZINE. 



NEW SERIES. DECADE II. VOL. VI. 



No. VI.— JUNE, 1879. 



OJElTG-T2SrjL.Tj AETICLES- 



I. — On the Occurrence of the Genus Ramipora (Toula) in 

 the Caradoc Beds of the Neighbourhood of Corwen. 



By R. Etheridge, Junior, F.G.S. ; 

 of the British Museum. 



(PLATE VI.) 



TO the recently published paper by my father, " Palaeontology of 

 the Coasts of the Arctic Lands visited by the late British 

 Expedition," etc., l I contributed some notes on the Polyzoa obtained 

 during the progress of the Expedition from the Palaeozoic rocks of 

 the regions visited. Amongst other forms I referred at some length 

 to Dr. E. Toula's genus Ramipora, and pointed out its affinities to 

 various genera of Palaeozoic Polyzoa, and more particularly to 

 Synocladia, King, in the following words : — " It appears to differ 

 from the first of these " {i.e. from Synocladia) " in the absence of 

 dichotomization of the stem and primary branches, so far as the 

 remains of it are known to us ; secondly, in the bilateral symmetry 

 of the latter ; thirdly, in the fact that the cells all open on the same 

 plane on each side the median keel, whereas in Synocladia the stems 

 and branches are divided longitudinally by several carinas, between 

 which the cell apertures occur. Again, in Ramipora both aspects of 

 the polyzoarium are carinate, but in Synocladia only one. Lastly, 

 in Synocladia the dissepiments all appear to be regularly celluli- 

 ferous, but in Ramipora this does not appear to hold good to the 

 same extent." 



Mr. Gr. J. Williams, of Tanygrisian, Festiniog, lately brought to 

 the British Museum some really beautiful impressions, in a grey 

 micaceous schist, of a Polyzoon found by himself in the neighbourhood 

 of Corwen, and which constitutes, I believe, an undescribed variety 

 of Toula's Ramipora Hoclistetteri. So far as I know, Ramipora has 

 hitherto been met with in the Permo-Carboniferous beds of the 

 Arctic regions only, and this extension backwards in time of a 

 Synocladia-like type is a point of much interest. I am also 

 acquainted only with one species, R. Hochstetteri, which the Corwen 

 form very closely resembles, in many points of detail. 



1 Quart. Journ. Geol. Soc. 1878, vol. xxxiv. pp. 568-639. 



DECADE II.— VOL. VI. — NO. VI. 16 



