BY D. MAWSOX. 435 



the Fe as FegO^. On account of its high titanium content and 

 fine character this ore is practically useless at the present 

 moment, but with success of experiments on titanium steels now 

 in progress, might at any moment assume commercial importance. 



Some of the finer non-calcareous bands in the Efate Soapslones 

 would make an excellent abrasive for polishing metals, and as the 

 cost of mining would be only nominal, good results might be 

 expected from such an enterprise. 



With respect to guano deposits, our discoveries were restricted 

 to scattered bodies of bat guano occurring in caves penetrating 

 the recent coral limestone. These deposits were found both in 

 Santo and Efate, but on account of the distance apart and of their 

 small dimensions — the largest of them containing a few hundred 

 tons only — they will never be of much commercial importance. 



Numerous small samples of copper, manganese, and other ores 

 supposed to have been collected in the Group, were examined by 

 us, but as nothing further was ascertained of their occurrence 

 they do not warrant further mention. 



Part ii.— Sec. 1. DETAILED GEOLOGY OF EFATE. 



i. Submarine Volcaxic Origin (Refer to Plate xxviii.)— The 

 island of Efate owes its immediate origin to extensive submarine 

 volcanic activity resulting in the piling up of thick beds of tuff, 

 which, later on, effectually hidden beneath a veneer of coralliferous 

 limestone, were raised to heights above sea-level. Over the 

 greater part, so perfect is this limestone veneer, as to lead the 

 casual observer to believe it to be a purely coral island. 



Careful examination discloses the fact that, underlying the 

 coral limestone at short distances, are fine-grained submarine 

 tuffs, shading off below into coarser varieties, in which distinct 

 fragments of a white pumice are visible; in other parts of the 

 island massive agglomerates are developed below the coral. 



As regards the location of the original crater, it would 

 undoubtedly be situated in the neighbourhood of the coarser 

 ejactamenta. Bearing this in mind, and recalling the distribution. 



