Manchester Memoirs, Vol. Ixiii (191 9), N^o. 3. 



III. — On a New Middle Carboniferous Nautiloid. 



( Ccelonauttlus trapezoidalis). 



BY 



J. Wilfrid Jackson, F.G.S., Assistant Keeper, Manchester Museum. 

 Read and received for publication, February i8th, i^i^. 



In a previous paper " On MoUusca from the Lancashire Coal- 

 Measures,"* I called attention to the fact that Mr. George Wild, in 

 1892,1 erroneously figured a Nautiloid from the " Roof of the Bullion 

 Coal, Townhouse, near Colne," under the name of ''^Nautilus sul>sul- 

 catus, Salter." Two figures are given by him (pi. II., fig. 5 ; pi. III., 

 fig. 3) representing different views of the same specimen, which now 

 forms part of the Wild Collection in the Manchester Museum. 



So far as can be ascertained, Salter never described or referred to a 

 Nautiloid under the name '''' subsulcatus" but Wild was in the habit of 

 attaching Salter's name to species of other authors, for example, 

 Nautilus cyclostomus Phillips ; Goniatiies striatus (J. Sow), etc., have 

 Salter's name appended in Wild's " Reference to the Plates."! 



Nautilus (now Ca'lonautilus) subsulcatus was founded and figured 

 by Phillips in his " lUust. of the Geol. of Yorks. " pt. II., 1836, p. 233, 

 pi. XVII., figs. 18 and 25, § on a specimen from the Carboniferous 

 Limestone of BoUand, Yorkshire, and the type is now in the British 

 Museum (No. C237, "Gilbertson Collection"). 



Wild's fossil, however, differs in several important characters, 

 especially in the more depressed and greater relative breadth of the 

 volutions, from Phillips' type-specimen, and, as stated in my previous 

 paper {op. cit., p. 449), belongs to a new species. 



Having the specimen with me when on a visit to the British Museum 

 in 191 2, I consulted Mr. G. C. Crick as to its afifinities and position 

 and he very kindly undertook to draw up a description of the species. 

 He pointed out that its nearest ally appeared to be Fleming's Nautilus 

 quadratus,\\ a. s^^ec\QS assigned by Foord ^ to his genus Calonautilus, 

 and from the trapezoidal form of the transverse section of the whorl he 

 suggested the name Ca'lonautilus trapezoidalis for the species under 

 review. 



* Geol. Mag., Dec. V., Vol. ix., No. 580, Oct. 1912, pp. 4-^9-453. 



t Trans. Manch. Geol. Soc. , XXI., i£92, pp. 397 and 400, pi. ii. and iii. 



J Trans. Manch. Geol. Soc, XXI., 1892, p. 400. 



§ Phillips in his " Reference to the plates " (p. 250) calls the species, N. suka- 

 tuhis, " and Brown, " Foss, Conch.," 1849, P- 3^, pi- XXV., f. 8, describes and 

 figures it again under that name. 



il J. Fleming, "Hist. Brit. Animals," 1828, p. S'l. 



IT A. H. Foord, Cat. Foss. Ceph., Brit. Mas., pt. 2., 189 1, p. 122. 



