called Gryphite Grit in the Cotteswolds. 201 



gether, destitute of the deep sulcation and large lateral lobe 

 whicli distinguish the dorsal surface of the convex valve in the 

 Cotteswold species. G. cymbium, Lam., is well exemplified in 

 the figures of Goldfuss* and Buvignierf, the larger figure of 

 Goldfuss representing the shell in an advanced stage of growth, 

 in which it acquii-ed a greater degree of elongation, the general 

 outhne constituting a tolerable resemblance to the object which 

 the name indicates. 



Another Gryphsea, associated in the same beds with G. cym- 

 bium, and of which it may possibly be only a variety, presents 

 a more near approximation to the Cotteswold species ; it has a 

 great degree of flatness and some irregularity which reminds 

 us somewhat of the true oysters ; it has also a lateral lobe and 

 sulcus, but much less prominent than in the Cotteswold shell, the 

 general elongated form resembling G. cymbium. M. Buvignier 

 considers it to be distinct from G. cymbium, and has named it 

 G. BroliensisX. 



The conspicuous sulcation and lobe which serves prominently 

 to distinguish the Cotteswold shell, is a feature which in a more 

 modified form is present in nearly the whole of the species of 

 this subgenus, of which it constitutes one of the characteristic 

 attributes ; for although the species of Gryphsea are more easily 

 distinguished than those of the true oysters, there exists never- 

 theless a large amount of variation. The adherent species will 

 be found to exhibit greater variability than the others ; it may 

 consequently be inferred, that the variation of form is connected 

 with the position which was accidentally retained by the attached 

 shell. The Cotteswold Gryphsea, which exhibits a considerable 

 difference of aspect, was frequently attached to another of the 

 same species, the shells being clustered together in masses. 



In conformity with precedents in similar instances, I dedicate 

 om* Cotteswold Gryphsea to the author who fii'st figured it in 

 the ' Geology of Cheltenham,^ and whose labours have contri- 

 buted so much to enlarge our knowledge of the fauna of the 

 Oolite. 



GryphjEa Buckmanni. 



Syn. Gryphcea cymbium, Murch. Geol. Chelt. 3834, p. 10. 



columba, Lonsdale, in Geol. Proceedings, 1835. 



cymbium, Morris, Catal. Brit. Foss. p. 109, 1843. 



cymbium, Geol. Chelt. 2nd edit. 1845, p. 75, 



pi. 7. fig. 3. 

 Sp. char. Shell transversely ovate, very convex, irregularly and 



* Petref. Germanise, tab. 7- fig- 3; tab. 85. fig. 1. 



t Geol. et Paleont. Dep. de la Meuse, Atlas, pi. 5. figs. 5, 6, 7- 



t Ibid. pi. 5. figs. 7, 8, 9. 



