54 HALKYARD, Fossil Foraminifera of the Blue Marl 



Typical examples frequent. The species however is at its 

 best at the top of the Marl where there is very little sand mixed 

 with the clay. This fact seems to show that the species flourishes 

 better on an oozy bottom. 



102. Bolivina tortuosa, Brady. 



Bolivina tortuosa, Brady, 1881, Quart. Journ. Micr. Soc, vol. 

 XXI, p. 57; and 1884, Chall Rep., p. 420, pi. LII, figs. 

 31-34- 



Not so frequent as the last species but still cannot be called 

 rare. Some of the specimens are fine and strongly-built, whilst 

 others are small, delicate, and more regular in the setting-on 

 of the segments. 



(The degree of axial curvature is very variable in the speci- 

 mens, in some cases practically non-existent.) 



Genus Pleurostomella, Reuss. 

 103. Pleurostomella alternans, Schwager. 



Pleurostomella alternans, Schwager, 1866. Novara-Exped., 



Geol. Theil II, p. 238, pi. VI, figs. 79, 80. 

 P. alternans, Brady, 1884, Chall. Rep., p. 412, pi. LI, figs. 22, 



23- 



Rare, occurring only in Gatherings No. 6 and 7. 



(The specimens are of a very short and broad type.) 



SUB-FAMILY CASSIDULININ^i. 



Genus Cassidulina, d'Orbigny. 

 104. Cassidulina subglobosa, Brady. 



Cassidulina subglobosa, Brady, 1881, Quart. Journ. Micr. Soc. 

 vol. XXI, p. 60; and 1884, Chall. Rep., p. 430, pi. LIV, 

 figs. 17a, b, c. 



Not rare, but the specimens are small though well-formed. 



105. Cassidulina laevigata, d'Orbigny. 



Cassidulina laevigata, d'Orbigny, 1826, Ann. Sci. Nat., vol. VII, 



p. 282, pi. VI, figs. 4-5. 

 C. Icevigata, Brady, 1884, Chall. Rep., p. 428, pi. LIV, figs. 1-3. 



The specimens are small, of a somewhat thick type, with- 

 out marginal carina. 



