492 REV. Gt. E. WHIDBORErE 01$ SOME EOSSILS 



to the Higher Oolites, which would hardly he the case were it a 

 young form of 0. Marshii, which is common below and rare above, 

 though extending to the Kimmeridgian. 



It seems doubtful whether 0. costata is really found in our Bajo- 

 cian. Lycett quotes it in the 'Annals/ 1850, from the Oolite Marl 

 of Minchmhampton ; and Sharp, in the Quarterly Journal, from 

 Northamptonshire ; but the former altogether omits it in his ' Hand- 

 book to the Cotteswold Hills.' A small oyster, between 0. costata 

 and 0. Knorrii, but distinct from both, is very common in the 

 Murchisoni- beds of Crickley, and occurs in those of Minchinhamptoi]. 

 It may be akin to 0. rugosa, Goldf., as.it is nearly smooth at first, 

 though it develops peculiar rounded ribs as it increases in size. 



OsTREA PALMETTA, Sow., Var. MONTIFORMIS. 



1815. ? Ostrea palmetta, Sow. Min. Conch, t. 111. fig. 2. 



1834. 0. rastellaris (Miinst.), Goldf. Petr.Germ. t. 74. fig. 8 (pars). 



1853. 0. gregaria, Morr. & Lye. Gt. Ool. Moll. pt. 2, t. i. fig. 2. 



1854. 0. gregaria, Morr. Cat. Brit. Foss. p. 173. 



1871. 0. gregaria*, Phill. ' Valley of the Thames/ t. 10. fig. 4. 



I am unable to believe that the oyster which commonly occurs in 

 our Great and Inferior Oolites, and has been referred to 0. gregaria, 

 Sow., really belongs to that species. Its size, the precipitousness 

 and irregularity of its ribs, and its gregarious habits seem to define 

 0. gregaria. Nor am I satisfied that 0. palmetta, Sow., is more than 

 a poor specimen of the same; for, from his description, it would 

 appear to have come from the Oxford Clay; but as it has been 

 stated by some to have come from the Great Oolite, I have retained 

 the name for the present. 



Morris and Lycett's figure clearly belongs to the shell that occurs 

 at Dundry, Cheltenham, &c. ; but it is a highly variable form. Mr. 

 Tawney seems to have joined it to 0. Marshii, Sow., as he has placed 

 shells of all sizes on a single tablet with that name. 



Besides the ordinary forms, I have found shells at Dundry and 

 Crickley which, with another Dundry fossil in the Bristol Museum, 

 seem undistinguishable from the shorter varieties of 0. rastellaris. 

 These are right valves, with a long, smooth, central convexity, sud- 

 denly surrounded by thirty or forty acute, simple, parallel ribs. 

 Their length is about twice their width, and their general shape 

 neat and regular. It is, however, impossible to determine the spe- 

 cific value of so variable a form without a larger number of ex- 

 amples. 



Osteea pyrtts, n. sp. Plate XV. figs. 4, 4 a. 



Shell small, long, very narrow, the length from the umbo being 

 nearly twice the breadth ; very deep below, the greatest depth being 

 just over the inferior margin. 



Umbo of left valve small, acute, and terminal, with an acutely 

 triangular ligamental groove ; surface smooth. 



The surface of attachment runs down the centre of the shell, and 

 is, in all instances, long, narrow, and very concave, as though it had 



