BY D. MAWSON. 447 



and small Globigerina; above, the foraminiferal remains become 

 relatively more numerous until beds of nearly pure limestone 

 (Sec.3, §3) up to 20 ft. in thickness are met with. Much of the 

 upper portion of the series was hidden from view in the sections 

 examined by us; such outcrops however, as were available, proved 

 to be coarse fragmentary types in which pebbles of foraminiferal 

 limestone and andesitic volcanic material figured. 



The series is much faulted and intruded by hornblende and 

 pyroxene andesite; interbedded bands 30 to 40 ft. thick of 

 andesite agglomerate were also noted. 



In most localities the beds dip in towards Losubunu at an^^les 

 varying between 27° and 53°; further west (the Wai Bubo outcrop) 

 (Plate xix.) they are completely reversed, dipping 55° S., 17° W, 

 The total thickness of the Miocene beds exposed on the Wai Bubo 

 is probably not less than 800 ft. 



iii. Later Yolcanic Series. — After a considerable 

 period of subdued activity, allowing of the accumulation of the 

 bedded Miocene limestones, intense folding and faulting seems to 

 have taken place, accompanied by extensive extravasations of 

 andesite lavas (Sec.3, §6) and agglomerates. On the Wai Bubo 

 thick beds of dark grey tuff (Sec.3, §4), composed mainly of 

 mineral fragments, through which are scattered occasional 

 Globigerina tests, are interbedded with this series, and dip 

 uniformly 27° due S. 



The lavas are usually pyroxene andesites, though more basic 

 varieties, especially among the later flows, are not uncommon, as, 

 for instance, an olivine pyroxene andesite from the base of 

 Lobweri, and several basalts outcropping between Tasiriki and 

 C. Ukuani. 



In the vicinity of the Losubunu the total thickness of this 

 series cannot be less than 5000 ft. 



iv. Bedded Rocks underlying the Recent 

 Raised Reefs . — The foundation-rocks immediately under- 

 lying the recent raised reefs in Santo, are similar to those found 

 elsewhere in the Group, and vary in character from types similar 



