OF SELBORNE. 9 



one into the other, the alternate flutings or grooves, and 

 the curved form of my specimen being much easier expressed 



OSTREA CARINATA. 



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

 and engraved. 1 



Gornua Ammonis are very common about this village. 2 



1 This is not the analogue of the cock's comb oyster, but belongs to 

 a different species which has not any living analogue, so far as is known. 

 The figures given above, which are copied from those of the original 

 edition, represent a shell of the Ostrcea carinata of Lamarck, so called on 

 account of the strong ridge or keel along the middle of each of its 

 valves. Though both are plaited oysters, the plaits or folds in each 

 are disposed in a different manner : nTthe cock's comb oyster they are 

 in the longitudinal direction of the shell, which, moreover, is rounded in 

 its general outline ; in the keeled oyster they pass transversely on each 

 side from the ridge or keel. 



The statement in the text, that White's specimens were obtained in 

 chalky fields, renders it necessary, as Mr. Bennett has judiciously re- 

 marked, to caution the reader against regarding it as a chalk fossil. 

 The fields below the chalk downs at Selborne, though white in the 

 appearance of their soil locally termed white malm belong in truth 

 to the formation known to geologists by the singularly inappropriate 

 name of green sand. To this formation the keeled oyster is peculiar ; 

 and it appears even to be limited, as a fossil, to the upper green sand, 

 the stratum on which the village of Selborne is built, and of which the 

 immediately adjacent enclosures consist. ED. 



2 The Rev. J. Mitford has said the same thing of Keynsham, between 

 Bath and Bristol, adding that " This has given rise to a fabulous legend, 

 which says that St. Keyna, from whom the place takes its name, resided 

 here in a solitary wood, full of venomous serpents, and her prayers 

 converted them into stones, which still retain their shape." See Espri- 

 ellrfs Letters from England, vol. iii. p. 362. ED. 



