18 THE BEITISH CONULARIiE. 



facial grooves and in the course of the growth-lines. It is possible, in the absence 

 of any other examples, thai the specimen should be regarded as an ornamented 

 shell, which is smooth ns the result of bad preservation. 



Horizon and Locality.— Caradoc : Lrwyn-yr-hwch, Beddgelert, N. Wales. 



Type. — Museum of Practical Geology (reg. no. 12657). 



Section IL—MONIL IFE UM. 



Ornamentation consisting exclusively of transverse ridges or of tubercles 

 arranged in transverse rows, without finer longitudinal ridges. 



(a) Internal raised longitudinal ribs (" septa" of Lindstrom, loc. cit.) present 



down the centre of each face. 



(a) Ornamentation extremely fine ; hardly visible without a lens. 



(i) Septa in pairs down the centre of each face. Faces equal. 

 Tubercles round and distinct. G. aspersa, Lindstrom. 



(ii) Septa in pairs down the centre of each face. Faces equal in 

 opposite pairs. Tubercles more or less confluent in longitu- 

 dinal rows. G. punctata, sp. nov. 

 (iii) Septa in pairs down the centre of each face, and also singly at 

 the angles of the pyramid (?). G. sp. cf. asjpersa. 

 (I>) Ornamentation coarse. Septa singly down the centre of each face. 

 (i) Transverse ridges quite smooth. C. tenuis, sp. nov. 

 (ii) Ridges finely tuberculated. G. tenuis, var. maculosa. 



(b) No internal longitudinal ribs present. 



(a) Ornamentation very fine, just visible to the naked eye or only visible 

 with a lens. 

 (t) Marginal and facial grooves with prominent edges. 



(i) Shell large ; ridges fine and regular, festooned across each 

 half face. G. corona ta, sp. nov. 



(ii) Shell small ; ridges form a sigmoidal curve from the facial 

 groove down to the marginal groove. 



C. sp. (mart/a rit if era ?). 

 (ft) Marginal and facial grooves simple. 



(i) Shell small ; ornamentation only seen under microscope. 



C. mieroseojrica, sp. nov. 

 (ii) Shell small ; ornamentation just visible to naked eye. 



G. sp. 

 (/>) Ornamentation visible to naked eye. 



(f) Tubercles round ; confined to the ridges. 



(i) Ridges coarse, turning up at an angle in the marginal 

 grooves ; faces flat. G. quadrisulcata, Sowerby. 



