20? 



exactly with those of Hampshire. Chama lamellosa, of Lamarck, is evi- 

 dently the same shell as chama squamosa, of Brander, foss. Hant. No. 86; 

 Chama calcarata of Lamarck, with distant transverse plicae, the superior 

 of which is echinated with long canaliculated spines, he says, may per- 

 haps be the same with the chama, No. 87, of Brander. Plate XIV. 

 Fig. 13, represents one of these species which I possess, from Grignon. 



Lamarck observes, that Bruguiere was acquainted with . C. lamellosa, 

 and that it is that which he speaks of under the name of C. rugosa; but 

 that he confounds it with a chama which is not fossil, and which is figured 

 in Lister and in Gualtieri. 



It is however probable that Lamarck is here mistaken. I find, among 

 my chamae, one which certainly shows that there exists a fossil chama, 

 to which the name C. rugosa is perfectly applicable. I also find one, 

 which I believe to be fossil, and which exactly agrees with the recent 

 shell figured by Lister, Tab. 217, Fig. 53, which has been considered as 

 C.foliacea by Gmelin, and, perhaps, as C. rugosa by Bosc. 



It is to the kind communication of Robert Scammell, Esq. of Ply- 

 mouth, that I am indebted for an account of a stratum of fossil shells 

 which he discovered at Haldon, or Hall-down, in the County of Devon. 

 Haldon is a hill, very nearly 850 feet above the level of the sea, and is, 

 from its northern to its southern point, about six miles in length, and 

 nearly three in breadth. 



On the sides and summit of the hill, along with the vegetable mould 

 are numerous flints : beneath these is, in some parts, a yellow, and 

 in others a white clay, with a mixture of sand arid silicious pebbles of 

 various sizes, to the depth of three or four feet. In some parts is found 

 a light brown sand, which, at the depth of about four fathoms, becomes 

 a firm concretion. The substratum of Haldon is, in some places, chalk, 

 and in others an extensive range of lime-stone. 



These strata terminate in others of various formation. Towards the 

 river F^x, they unite with a long range of amygdaloid : they descend 

 into the schist of Ashton ; which is here, as in many other instances, sue?- 



