BY W. G. WOOLNOUGH. 461 



This inference is strengthened by the fact that hot springs do 

 occur in the north-west part of the plain, west of the Tavua 

 River. From what I could make out from rambling native 

 descriptions, these springs, of which there are two sets, must be 

 considerably hotter than those in any otlier part of the main 

 island, though probably not so hot as those of Savusavu Bay in 

 Vanua Levu, described bj^ Guppy.* I understood that the 

 water was at times hot enough to severely scald one. The flow 

 appears to be spasmodic and, the natives stated, sometimes 

 violent. 



In my former paper I suggested the possibility of a fault 

 bounding the Nadarivatu scarp. f Most of my correspondents 

 have taken my statement to mean that such a fault had definitely 

 been proved to exist. I did not intend such an impression to be 

 created; even at the time I regarded the existence of such a fault 

 as highly problematical, and further investigations have shown 

 that no such fault exists in this place. I have now no doubt 

 that Dr. Guppy's explanation^ of this plain as a recently elevated 

 plain, chiefly of marine accumulation, is the correct one. 



Westwards, the area extends at least as far as the Sigatoka 

 River at Nadrau. Sections of the columnar andesite exposed 

 there, and formerly described as an augite andesite, show that 

 the rock is much more basic than was supposed, a limburgite in 

 fact, very similar to the Nadarivatu rock but more basic. The 

 strong curvature and divergence of the columns indicates that 

 the cooling surface in contact with the rock was irregular. There 

 are two flows separated by a bed of fine tuff. The lower one 

 rests on a coarser tuff containing beautifully perfect augite 

 crystals, and recognisable remains of marine organisms. 



The most interesting feature of the area under consideration 

 is the shell-bearing conglomerate at Nasoqo, previously described. § 



* Guppy, H. B., " Observations of a Naturalist in the Pacific," etc., 1903. 

 Vol.i.,p.25. 



t loc. cit., Plate xxxiv. 



X Private communication. 



§ Former paper, p. 477. 



