BY FREDEUICK CHAPMAN. 747 



This is a whitish or cream-coloured limestone, of fairly compact 

 texture, and having tlie appearance of a hard coral-reef rock, 

 with occasional fragments of decomposed volcanic rock (andesite) 

 showing on the fractured surface. 



Subjected to a microscopic examination, this rock is seen to 

 consist of numerous tests of foraminifera, both large and small, 

 the former being usually fragmentary, or showing signs of 

 abrasion before being cemented into the rock. The matrix con- 

 sists of a fine granular paste, and its earthy or chalk}'^ appearance 

 in thin sections leads one to conclude that calcareous algae, 

 although no longer apparent in the rock, played an important 

 part in its original constitution. Besides foraminifera, the fol- 

 lowing organic remains were seen : — Lithothamnium (L. ramo- 

 sissimum Reuss sp.) and probably Lithophylluin (growing in a 

 thin foliciceous manner and encrusting other organisms); numerous 

 echinoid spines; also polyzoa. 



The Foraminifera observed in this rock are : — 



Orhidina univei^sa D'Orb. Section showing the initial ' globi- 

 gerine ' series of chambers. 



Truncatulina sp. 



Carpenteria rhaphidodendron Moebius. 



Pulvinulina cf. repanda F. k M. sp. 



Gypsina globulus Reuss sp. 



Miogypsina hurdigalensis Giimbel sp. 



Folytreina planum Carter. Growing in alternate layers w^ith 

 ('*) Lithophyllum. 



Amphistegina lessonii d'Orb. Very large specimens with 

 numerous whorls, probably the microspheric form of the species. 



Ope7XuUna sp. In fragments only. 



Lepidocydina angularis Newton &l Holland. 



L. ayidrewsiana Jones & Chapman. 



L. verbeeki Newton & Holland. 



