GKOLOGY OF FOLKI'ISTONH — THE OAULT. 
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its imnionso calcai'cous deposits. Nacula pectinaia and Numla ovata 
ai'o also common and characteristic bivalves of the gault. 
Lign. 28. — Nucala bii'irijufa. Ijign. 29. — Niicula oriiatmaimu. 
And of the genus Nucula we figure also two other species, which 
are occasionally to be found, which, from their peculiar and beautiful 
ornamentation, can be readily determined. 
Lio-ii. 'iO.—jPlicufiilii peeteiioides. 
Lign. 31. — Odrea Hauliniana. 
Amongst the other bivalves which the collector is likely to include 
