The, Olive and Chama Beds. 



abundance of specimens of Oliva Branderi, forming the 

 equivalent to number eighteen in Dr. Wright's arrangement, 

 and which, when worked, emits a strong smell of sulphur. 



Immediately under the Olive Bed, as seen in the opposite 

 section (IL)> taken immediately on the west side of the Bunny, 

 rises grey sand, seventeen feet and a half in thickness, possess- 

 ing only a few casts of shells. The next bed, however, composed 

 also of grey sand, rising about three hundred yards farther on, 

 is, perhaps, the richest in the whole of this Marine series, and 

 its shells the best preserved. It may at once be recognized 

 by the profusion of Chama squamosa, from which it has been 

 called the Chama Bed. Specimens of Area Branderi and Solen 

 gmc'dis may be found here as perfect as on the day they were 

 deposited. 



A little farther on, nearly under the Gangway, rises the 

 Barton clay, encrusted with Crassatella sulcata,* And here, 



* Some of the most characteristic shells in this bed may perhaps be 

 mentioned : 



Pleurotoma exorta. Sol. Scalaria reticulata. Sw. 



Terebellum fusiforme. Lam. Scalaria semicostata. Sow. 



Murex minax. Sol. Littorina sulcata. Pilk. 



Murex asper. Sol. Solarium plicatum. Lam. 



Murex bispinosus. Sow. Hipponyx squamiformis. Latft. 



Typhis pungens. Sol. Fusus porrectus. Sol. 



Voluta ambigua. Sol. Fusus errans. Sol. 



Voluta costata. Sol. Fusus longajvus. Lam. 



Voluta luctatrix. Sol. Bulla constricta. Soiv. 



Dentalium striatum. Sow. Bulla elliptica. Desk. 



I scarcely need, I hope, refer the reader either to Mr. Edwards' Mono- 

 graph on the fycene Mollusca, 1849, 1852, 1854, 1856, or to Mr. Searles 

 Wood's Monograph on the same subject, both in course of publication by 

 tke Palaeontographical Society. There is an excellent table of the Barton 

 shells, by Mr. Prestwich, in the GeologicalJournal, vol. xiii. pp. 118-126. 



I I 241 



