NATURAL HISTORY OF SELBORNE. 9 



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 Mytilus, and the species of Crista Galli ; 

 called by Lister, Rastellum ; by Rumphius, Ostreum 

 plicatum minus ; by D' Argenville, Auris porci, 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 engraving from a perfect one. In the superb 

 museum 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. 

 The curious foldings of the suture the one into the other, 

 the alternate flutings or grooves, and the curved form of 

 my specimen are much easier expressed by the pencil than 

 by words. 



Cornua Ammonis are very common about this village. 

 As we were cutting an inclining path up the Hanger, the 

 labourers found them frequently on that steep, just under 

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

 lane above Well-head, in the way to Emshot, they abound 

 in the bank, in a darkish sort of marl ; and are usually very 

 small and soft : but in Clay's Pond, a little farther on, at 

 the end of the pit, where the soil is dug out for manure, 

 I have occasionally observed them of large dimensions, 

 perhaps fourteen or sixteen inches in diameter. But , as 

 these did not consist of firm stone, but were formed of a 

 kind of terra lapidosa, or hardened clay, as soon as they 

 were exposed to the rains and frost they mouldered away. 

 These seemed as if they were a very recent production. In 



