334: Mr. Parkinson on the Strata, 



shell appears to have been smooth ; and at Its full size about four 

 inches in length : the columella has four folds, and the shell is formed 

 by about six spiral turns, the last of which makes two thirds of the 

 shell, dilating at about its centre, and contracting nearly equally 

 upwards and downwards. The specimens yet seen give no oppor- 

 tunity of judging of the lip, or of the termination of the spire. 



The Essex reversed ivhelk, as it has been termed, murex contrar'ius 

 Linn. Hist. Conch, of Lister, /rtZ*. 950,^. 44. h. c. which is here very 

 abundant, does not appear to be known in any other stratum of the 

 island. The fossil shell, with the whirls in the ordinary direction, 

 is sometimes found in this stratum.* 



It has been said that the recent analogues of both these shells are 

 found in the adjoining sea. A recent shell is indeed found which 

 very nearly agrees with the ordinarily turned shell in its general 

 characters : but there appears no authority for supposing that the 

 analogue of the left -turned variety has been discovered there. 



Among those recent shells, the resemblance of which to the fossil 

 ones of this stratum is such as appears to render a comparison 

 by an experienced conchologist necessary, may be enumerated : 



Patella tuigarica. Patella mlUtaris, Patella sinensis, (Calyptraa, 

 Lam.) Patella Jissura, (Emcirginula, Lam.) one or two species of 

 Patella, with a perforation in the apex, (Fissurella, Lam.) Nerita 

 glauc'ina, Nerita canrena, (Natica, Lam.) Turbo tercbra, (Turri- 

 tella, L^im.) Murex corneus, Murcx erinaceus, Strombus pes pelicani, 

 Cyprcea pediculus, with no sulcus along the back, Pholas crispatus, 

 in fragments, Solcn ensis, and Solen siliqua, in fragments, Cardiuni 

 cdule, Cardium aculeatum ? bearing the size and form of this shell, 



* It is erroneously stated, Organic Remains, to). III. p. G6, that this shell has not 

 bccu yet raentioucJj as found in this stratam j since it is jo particuUrisod by Dale. 



