CARBONICOLA RUGOSA. 49 



2. Caebonicola eugosa (Brown). Plate II, figs. 7, 8, 8 a. 



Pachyodon btjgosus, Brown. Ann. Mag. Nat. Hist., vol. xii, p. 391, 1843. 

 Unio rugosus, Brown. Foss. Conch., pi. xv, figs. 6, 7 ; pi. lxxiii, figs. 14, 15, 1849. 



Specific Characters. — Subtriangular, ventricose. Umbones massive, subcentral, 

 obtuse, tumid, incurved, and contiguous. Anterior end swollen ; anterior border 

 rounded, meeting the superior border at an angle rather greater than that of a 

 right angle. Posterior end swollen ; the superior border slopes rapidly down- 

 wards, forming a bluntly-curved posterior border. Inferior border uniformly 

 convex. 



Lunule broad, deep, and well marked. Ligament large, erect, extending from 

 between the umbones half the length of the posterior hinge-line. 



Valves uniformly convex, covered with fine stria? and rugse of growth. 

 Interior unknown. 



Dimensions : Antero-posteriorly. Dorso-ventrally. Laterally. 



Mr. Wild's specimen . 62 mm. 48 mm. 42 mm. 



Specimen in Geol. Survey 48 mm. 41 mm. 

 Mus. (incomplete) 



Localities. — Ironstone, Hebden Bridge, Cant-Clough, Burnley, — horizon 

 doubtful. 



Observations. — This form appears to be allied to C.robusta, to which Mr. Salter 

 (' Geol. Surv. Mem., Wigan,' p. 37, 1862) was inclined to refer it. But there are 

 certain characteristics, as the more central position and the shape of the umbones, 

 the deep elongated lunule, and the comparatively greater tumidity of the shell, 

 which, taken in connection with the different horizon at which the shell occurs, 

 have induced me, for the present, to retain Captain Brown's name. His original 

 specimen is said to have come from the Hebden Bridge Ironstone, and the figure 

 given is that of a perfect specimen ; but I have been unable to trace it. 



I only know of two specimens, both from the neighbourhood of Burnley, and 

 these have been kindly lent me to figure by the Director-General of the 

 Geological Survey and Mr. George Wild, but unfortunately both of these 

 specimens are imperfect posteriorly. 



The exact horizon of these specimens is doubtful, but it is certainly low down, 

 possibly Yoredale. Mr. Wild writes me that he has no notes of the bed from 

 which he obtained his specimen. That belonging to the Geological Survey 

 Collection is labelled " Coal-measures." 



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