6 THE NATURAL HISTORY 



minus ; by D'Argenville, Juris Porci, s. Crista Galli ; and by those 

 who make collections cock's comh. 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 1 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 zoo- 

 phyte, 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 being much easier expressed 

 by the pencil than by words, I have caused it to be drawn and 

 engraved.^ 



Comua 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 dimen- 

 sions, 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 the chalk-pit, at the 

 north-west end of The Hanger, large nautili are sometimes 

 observed. 



In the very thickest strata of our freestone, and at considerable 

 depths, well-diggers often find large scallops or pectines, having 

 both shells deeply striated, and ridged and fuiTowed alternately. 

 They are highly impregnated with, if not wholly composed of, 

 the stone of the quarry. 



1 [The nuiseum at Leicester House was formed by Sir Ashton Lever at Alkring- 

 ton, near Manchester, and afterwards removed to London. In Letter XVIIL to 

 Barrington, White calls it " the most elegant private museum in Great Britain". 

 It was sold by lottery in 1785, and dispersed by auction in 1806.] 



'^[White's fossil is Ostrea caHnata, Schloth, a well-known cretaceous species. 

 Ostrea crista-ga Hi, L. , the cockscomb oyster of the Indian Ocean, is similar, but not 

 identical.] 



^[Ammonites.] 



