282 Christmas Island. 



Rotalia schroeteriana (Parker & Jones). 



Some very excellent sections, in both transverse and vertical 

 direction, are seen in this specimen (No. 522). 



Rotalia dathrata, Brady. (PL XX, Fig. 2.) 

 Rotalia clathratn, Brady, 1884, Rep. Chall., vol. ix, p. 709, pi. 107, figs. 8, 9. 



One of the more striking forms in No. 522 may be referred to 

 the above species. In section the surface reticulation is represented 

 by square-ended projections. The shell-wall in this species, as in 

 the other allied Rotalice, is coarsely tubulated. Longest diameter 

 of the test -^g inch. 



This is not an isolated instance of a recent species occurring for 

 the first time in the Miocene of Christmas Island, as will be seen 

 by referring to subsequent pages. It is interesting to note that 

 this rare form has been found only in the South Pacific, in shallow 

 or moderately shallow water. 



Gypsina globulus (Reuss). 



This species is represented in this rock- section by several 

 specimens. They are rather more irregular in internal structure 

 than those of the preceding limestone (No. 2), and are altogether 

 smaller in size. 



AmpMstegina lessonii, d'Orbigny. 



This is again common in the section before us. It may be 

 distinguished from Pulvinulina elegans (d'Orb.) by the sigmoid 

 form of the septa and the alar extension of the chambers on the 

 inferior surface. 



Heterostegina depressa, d'Orbigny. 



Frequent, but not so common as in the foregoing limestone 

 (No. 2). 



The last-mentioned limestone (No. 522) is succeeded by a second 

 sheet of basalt with accompanying beds of tuff. The limestones 

 which follow are of considerable thickness, and as a rule are 

 crowded with Orhitoides ; although there are some exceptions 

 where these are rare. 



The genus Orhitoides is represented, in the limestones now about 

 to be described, by the Lepidocycline subgenus only, and this 

 seems to indicate that the beds are related to others, in the same 



