66 



FOYE. 



the center of the island, where the elevation approximates 80 feet. 

 The limestone mass is therefore basin-shaped. The seaward cliffs 

 are usually unscalable. Access to the interior of the island, is how- 

 ever, possible by way of local solution pits in the limestone. The 

 interior is honeycombed with pits and caverns. Here and there a 

 flat area of an acre or so is covered with a red, residual soil on which 

 the natives grow coconuts. Some of the caverns extend below sea- 

 level and in them the tide rises and falls. 



On the seaward face of the enclosing ridge there is frequently a 

 bench at an elevation of 100 to 125 feet. The general dip of the 

 limestone forming the cliffs at the northern side of the island is 10° 



Wangava 



KAMBARA 



M«rxmbo 



Figure 31. 

 Marambo. 



Sketch Map of the Islands of Kambara, Wangava and 



to 12° outward. The rock is composed of coral heads in place (form- 

 ing nearly 30 per cent of the whole) and coral and shell rubble. 

 Corals in place were found within the dissected mass at sea-level. 

 There is no evidence of a volcanic substructure in Kambara even 

 within its low interior basin. It is believed, therefore, that the 

 visible island essentially represents a single mass of limestone, in 

 places 350 feet high. There is no structural evidence that the coral- 

 liferous limestone is a veneer on older Tertiary limestone. The 

 observed attitude of the bedding shows the limestone to be every- 

 where conformable and of low dip. The conclusion follows that the 

 island was formed by subsidence. 



