54 Proceedings of the Royal Physical Society. 



mented by those of Mr E. W. Binney and Professor E. Hull, 

 it is often associated with true marine forms.* 



The great abundance in which Anthracosia occurred in the 

 true Coal Measures is nowhere better shown than in the Cam- 

 buslang marble, which is a bed of some thickness chiefly 

 composed of shells of this genus.f No less than twelve 

 species are said to occur in the Coal Measures of Scotland, 

 but doubtless much revision is required here. J 



In the Family Gardiidce has been placed perhaps the most 

 peculiar shell of the Carboniferous period — the genus Conocar- 

 dium (Bronn). It is better known in this country as Pleuro- 

 hynchus (Phillips), but the former has priority of date. The 

 hinge structure is not thoroughly known, and would afford a 

 very interesting study. Conocardium has been placed in the 

 aberrant group Rudista, and, although this is probably too 

 extreme a reference, it still remains doubtful if it is a true 

 member of the Cardiidce.§ Internally the shell of Conocar- 

 dium is strengthened by ribs, which appear to vary accord- 

 ing to species. 



The Family Gyprinidce, or as it is called by some the Glos- 

 sidoe, is represented by shells placed in the genus Cypricardia 

 (Lamarck), but which I am not at all clear possess the hinge 

 structure of the latter as presented to us in the living shells. 

 The Carboniferous species are of great interest as exhibiting 

 some peculiar modifications of form. Two such have been 

 ably described by Mr James Armstrong II from Scotch rocks 

 of that age — G. acuticarinata and G. crehricostata. Another of 

 the so-called Gypricardice is probably referable to King's 

 genus Plenrophorns^ and it is possible that the latter may 



* Salter, Iron Ores, p. 227. 



f J. Young, "On the Fossil shells Anthracosia, Anthracomya, and An- 

 thracoptera, found in the Lanarkshire Coalfield" (Proc. Nat. Hist. Soc, 

 Glasgow, 1864, i., p. 84). 



X Armstrong and Young, Cat. W. Scot, Foss. ,p. 52 ; Brown, Foss. Conchol, , 

 1849, p. 177 ; id. " Description of some New Species of the Genus Pachyodon " 

 (Annals Nat. Hist., 1843, viii., pp. 390-396). 



§ Meek and Hayden, Pal. Up. Missouri, p. 97. 



II " Descriptions of Two New Species of Cy2)ricardia from the Carboniferous 

 Limestone of Lanarkshire" (Trans. Glasgow Gool. Soc, 1865, ii., pt. 1, 

 p. 28). 



H Mon. Perm. Foss., 1850, p. ISO. 



