DESCRIPTION OF PLATE IV. 



In-Ml Mll'll- IKliM Till I.nU I K l.l.TI \'-^.\H DEI'mM'Iv 



Fig. 1 — Corbis corrugata, from the sand-rock, Atherfleld : the figure is 

 one-half tlie size in linear dimensions of the original. 



2. — Trigonia caudata . from the sand-rock, Atherfleld. 



3 GerviUia anceps; from the Cracker Rocks, Atherfleld. a, denotes 



the markings of the hinge, which are seen in consequence of the 

 valves being slightly displaced. Tt is represented half the size 

 linear, of the original. These shells are often much larger, and 

 more elongated than in the figure. 



4. — Venus striato-costata ; a small shell, common in the Cracker 

 Rocks at Atherfleld ; the figure is twice the size of the original 

 in linear dimensions. 



5. — Area TLaulini ; from the sand-rock, Atherfleld. 



6. — Tenia Mullet i ; from the lower beds of sand in junction with the 

 Wealden ; Sandown Bay. The figure is hut half the size of the 

 original, a, the structure of the hinge ; by comparing this 

 figure with a, figure 3, the difference of the hinge in the genera 

 Tenia and GerviUia will he recognised. This large and remark- 

 able shell is highly characteristic of the lower beds of the Green- 

 sand. 



7. — Venus pun. i , from Shanklin Cliff. 



