302 Proceedings of the Royal Physical Society. 



AVoodward, F.E.S., who also entered into the question, that 

 Mceonia grandis (Dana), can only be regarded as a synonym of 

 Pachydomus glohosus (J. de C. Sowerby). 



Log. and Horizon. — Pelican Creek, half a mile above 

 Sonoma road-crossing, in a highly fossiliferoiis concretionary 

 and feruginous mtidstone. Pelican Creek, in a sandstone 

 above the Garrick coal seam, both horizons in the Marine 

 Series (Nos. 58 and 63). 



Collector. — E. L. Jack, Esq. 



Genus Sanguinolites— if' C'o^/, 1844. 



(Synop. Carb. Limestone Foss. Ireland, p. 47 ; Brit. Pal. Foss., 1852, fas, 2, 



p. 276.) 



Sanguinolites, sp. ind.— PL XVI., fig. 54. 



Compare Sanguinolites clava (M'Coy), Brit. Pal. Foss.j 1853, fas. 3, p, 504, 

 t. 3F, f. 12.) 



Ohs.^With the exception of a somewhat shorter and more 

 gibbous form, I am unable to distinguish this species from 

 Professor M'Coy's S. clava. The specimen is, I believe, a 

 cast of the exterior, as there are no traces of muscular impres- 

 sions left, and the valves have by pressure been slightly 

 displaced. Notwithstanding this, it is easily seen that the 

 shell possessed a much more gibbous and rotund habit than 

 S. clava, the relative convexity of the valves immediately 

 below the beaks being greater. The rapid attenuation of the 

 flanks towards the ventral margin and the thinning-off of the 

 posterior end are as in S. clava, and there also existed a well- 

 marked lunette and escutcheon, although the latter was much 

 shorter than in M'Coy's species. Lastly, the posterior slope 

 is more defined in the Australian form, and the valves were 

 closed posteriorly. Taking all these characters together, it must 

 be conceded that, in all probability, the two species are distinct. 

 A useful comparison might be made between Mr Jack's shell 

 and two Australian species described by Dana, did we only 

 know more about them, viz., Edmondia (?) {Pkoladomya) 

 Glendonensis* and Sangicinolites or Edmondia (?) (Pkoladomya) 

 undata.f The first, as figured by Dana, is a crushed-down 

 * Geol. U.S. Exploring Exped. Atlas, t. 2, f. 12. f Loc. cit., f. 11. 



