APPENDIX TO PAET IL 



DESCRIPTIONS OF TERTIARY FOSSIL SHELLS 

 FROM SOUTH AMERICA. 



By G. B. SOWEKBY, Esq., F.L.S., &o. 



Mactea ? EtraATA. — PI. II. fig. 8. 



Mactra f testa oblongd, tenui, turgidd, latere antico altiore, rotun- 

 dato, postico longiore, acuminato ; lineis incrementi rugas con- 

 centricas efformantibus. 



The shell itself is changed into Gypsum. 

 Santa Cruz, Patagonia. 



Mactea Daewistii. — PI. II. fig. 9. 



Mactra testa ovali, submquilaterali, subventricosd, tenuiusculd, Icevi, 

 concentrice striata, antice rotundatd, postice obsoletissime sub- 

 quadratd. 



It is impossible to get at the hinge, wherefore it cannot be 

 ascertained positively to be a Mactra. 



Santa Cruz, Patagonia. 



Ceassatella Lyellii. — PI. II. fig. 10. 



Crassatella testa oblongd, planiusculd, tenuiusculd, postice angulatd, 

 margine postico dorsali declivi, superjieie sulcis obtusis, remotis, 

 longitudinalibus ornatd. 



This species most nearly resembles Crassatella lamellosa of 



