

Note on the Gryphsea of the Bed called Gryphite Grit in the 

 Cotteswolds. By John Lycett, Esq. 



Read February 1853. 



The lower bed of the upper ragstones in the Cotteswold Inferior 

 Oolite exhibits an immense profusion of a well-known Gryphsea, 

 and this circumstance, together with the very limited strati- 

 graphical range of the shell, combines to render it of much 

 importance to the geologist, as it affords a certain guide to that 

 portion of the Inferior Oolite. This Gryphsea has been univer- 

 sally accepted as the G. cymbium of Lamarck, but the position 

 of that species upon the continent is known to be the Middle 

 Lias, of which it is considered to be one of the characteristic 

 forms, and a reference to the figures and descriptions of Lamarck's 

 shell proves that it is perfectly distinct from the Cotteswold 

 species. In the first edition of the ' Geology of Cheltenham/ by 

 Sir R. Murchison, the Gryphsea is tabulated G. cymbium, and 

 this name was copied into the second edition, in which however, 

 fortunately, an illustration was given of it at pi. 7. fig. 3. 

 Subsequent lists of Inferior Oolite fossils have included Gryphaa 

 cymbium. It does not appear that Lamarck's species has been 

 recognised in the lias of England ; it possesses a general resem- 

 blance to G. incurva and G. obliquata, except that the larger 

 valve has much less convexity, the beak is much less incurved, 

 and has a small area by which it was attached to other bodies ; 

 the upper valve is also much larger ; the margins of the valves 

 are regular and not sinuous ; the height of the shell always much 

 exceeds the lateral diameter, sometimes in the proportion of 6 

 inches by 3 ; it is nearly, and in 3ome instances perhaps alto- 

 gether, destitute of the deep sulcation and large lateral lobe 

 which 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 acquired a greater degree of elongation, the general 

 outline 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 



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



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



