312 On the Organic Remains 



reous sandstone boulders ; but the small portion of shell 

 attached is not sufficient to identify the species. 



Turbo ornatus, and muricatiis imbedded in a boulder with 



Turritella muricata. A pyritous cast of a turritella in calca- 

 reous sandstone, an imperfect shell in an oolitic nodule, and 

 casts of others in sandstone, are all too imperfect to receive a 

 specific name. 



Venus. Casts of two or three species occur. 



Unio Listeri, hybridns, crass issimiis, concinnus, and a very 

 laterally elongated species, not yet figured. 



EchinidcB, 



All the fossilized remains of this order, that I have met with 

 in this county, were originally derived from the chalk strata. 

 I have not seen a single specimen in the debris of any other 

 stratum. They almost invariably occur as casts in flint — the 

 shell destroyed. There are instances of casts entirely sur- 

 rounded by the flint ; fracture liberates the cast, and exhibits 

 the impression of the exterior of the shell : occasionally the 

 shell is preserved enveloped in flint ; more rarely, the minera- 

 lized shells, filled with chalk or flint, are found in chalk boulders. 

 I possess the following : — 



Cidaris mammillata, with several spines in contact, but not 

 attached ; in a chalk boulder. Cidaris papillata, and corol- 

 larls. The long cylindrical spines of cidaris mammillata, and 

 the fusiform or cucumerine and clavated spines of cidaris 

 papillata, are not unfrequently met with in chalk boulders, or 

 their impressions on flint. 



Echinocorys scutatus, casts in flint of both gibbous and 

 depressed species or varieties. The same varieties of 



Conulus albogalerus ; and echinodiscus, scutella of Lamark. 



Spatangus cor marinum, ovum marinum (brissus), and casts 

 of a species of this brissus, occur, with its dorsum singularly ele- 

 vated at the commencement of the dorsal groove. 



Stelleridce. 



Asterias semilunatus (pentagonaster semilunatus). Parkin- 

 son's Organic Remains, &c., vol. iii., tab. I. fig. 1. I possess a 



