20 cuEioirs rossiL shells. 



LETTER III. 



TO THE SAME. 



The fossil shells of this district, and sorts of stone, such as 

 have fallen within my observation, must not be passed over 

 in silence. And, first, I must mention, as a great curiosity, 

 a specimen that was ploughed up in the chalky fields, near 

 the side of the Down, and given to me for the singularity of 

 its appearance, which, to an incurious eye, seems like a 

 petrified fish of about four inches long, the cardo passing 

 for a head and mouth. It is in reality a bivalve of the 

 Linnsean genus of mytilis, and the species of crista galli: 

 called by Lister, rastellum ; by Eumphius, ostreum plicatwm, 

 minus ; by D'Argenville, av/ris pord, s. crista galli ; and by 

 those who make collections, cock's comb. Though I applied 

 to several such in London, I never could meet with an 

 entire specimen ; nor could I ever find in books any engrav- 

 ing frfim a perfect one. In the superb musemn at Leicester 

 House, permission was given me to examine for this article ; 

 and though I was disappointed as to the fossil, I was highly 

 gratified with the sight of several of the shells themselves in 

 high preservation. This bivalve is only known to inhabit 

 the Indian Ocean, where it fixes itself to a zoophyte, known 

 by the name gorgonia. 



Cornua ammonis* are very common about this village. As 

 we were cutting an inchiiiag path up the Hanger, the 

 labourers found them frequently on that steep, just under 

 the son, in the chalk, and of a considerable size. In the 

 lane above "Wellhead, ia the way to Emshot, they abound in 



* There is a village in the west of England, remarkahle for the quantity it 

 possesses of the " Cornu ammonis." The name of it is Keynsham, between 

 Bath and Bristol. This has given rise to a fabulous legend, which says that 

 St. Kcyna, from whom the place takes its name, resided hero in a solitary 

 wood, full of venemous serpents, and her prayers converted them into stones, 

 which still retain their shape. — See Espriella's Letters from Enc/land, vol. iii, 

 p. 362, — Rev. J. Mitfokd. 



