394 MR. H. BOLTON, F.R.s.E., ON [Feb., 1904. 



The genera are those of the Yoredales and Carboniferous 

 Limestone. 



ISTautiloid forms are as follows : — 



Ephipphioceras costatum. 



,, clitellarium. 



Coelonautilus subsulcatus. 



„ quadratus. 



Pleuronautilus falcatus. 

 Temnocheilus concavus. 



„ carbonarius. 



These occur rarely in the shales and "bawm-pots" over the 

 Mountain Four Feet and Bullion Seams in the Burnley and 

 Rossendale districts. 



Examples of most of these species are, I believe, in the 

 Manchester Museum. 



The genus Orthoceras is represented by several species in 

 the Lower Coal measures, all of which stand in great need of 

 illustration and description. The specific names given by 

 the older workers are of little value as guides, and some of 

 the specific terms used by them are not recognised by later 

 workers. 



One form recorded from the shales about the Upper 

 Mountain mine at Hoyle Hey Clough, near Bacup, has often 

 to the writer's knowledge been recognised as 0. teres, a 

 species placed by Crick and Foord (Cat. Foss. Ceph., Part I., 

 p. 121) in the Carboniferous Limestone of Scotland. A second 

 species has received the name of 0. cinctum, which is a 

 synonym for 0. discrepans of the Belgian Carboniferous Lime- 

 stone. 



Still another form is the Orthoceras obtusum of Brown, 

 a species moderately common in the " bawm-pots " over the 

 Mountain Four Feet and Bullion seams. This species is not 



