88 APPENDIX. 



No. V. 



In appending a catalogue of Tertiary shells, it has heen thought best to employ 

 the following nomenclature of the strata to which they belong: 

 Upper Tertiary, Newer Pliocene, or Quaternary, 

 Middle Tertiary, or Upper Marine,* 

 Lower Tertiary, or Eocene. 

 Mr. Conrad found the following shells in the Newer Pliocene on the Potomac, 

 about three miles from its mouth : 



UNIVALVES. 

 Acteon melanoides, Conrad ; Crepidula convexa, Say ; C. glauca, Say ; Fusus 

 cinereus, Say ; Nassa obsoleta, Say ; N. trivittata, Say ; Natica duplicata, Say ; 

 N. interna, Say ; Ranella caudata, Say ; Scalaria. 



BIVALVES. 

 Area transversa, Say ; A. ponderosa, Say ; Corbula contracta, Say ; Rangia 

 cyrenoides; Cytherea Sayana, Conrad; Mactra lateralis, Say; Mya arenaria; 

 My tilus hamatus, Say ; Nucula laevis, Say ; N. acuta, Con. ; Pandora trilineata, 

 Say ; Petricola pholadiformis, Lam. ; Pholas costata, Lam. ; Sanguinolaria fusca, 

 Con.; S. lusoria, Con.; Solecurtus caribaeus; S. ensis, Lin.; Venus mercenaria, 

 Lam.; Venus. 



In the preceding list, but three species occur which have not been satisfactorily 

 identified with existing shells of the middle and southern coasts. 



In addition to these, the Colombella avara of Say and some other species were 

 found in digging a well in the city of Charleston. They are in Professor Rave- 

 nel's collection, and are as brilliant in their colors and polish as living shells. No 

 extinct species was found among them. 



• See note at the end of the following catalogue. 



