480 THE CONTINENTAL ORIGIN OF FIJI, 



ciystals of augite varying from submicroscopic individuals up to 

 half an inch in length. 



With the exception of the highh^ inclined members, which form 

 part of actual cones, it is probable that most of the tuffs are 

 submarine in origin. The uniform gentle dip (about N.W. at 

 9'') over wide areas is difficult to explain on any other hypothesis. 

 Actual evidence is available at Nadrau where the tuff under- 

 lying the columnar andesite contains numerous shell fragments. 

 I was unable to obtain any perfect specimens, but found one 

 recognisable ear of a Pecten. A large fragment of coral, 

 Goniastrcea sp., was also found imbedded in the tuff at an eleva- 

 tion of 1290 feet (aneroid) above sea-level. 



Coarse agglomerates, similar to those met with so abundantly 

 in the first traverse, are not at all extensivel}" developed in this 

 region. A great belt extends from Nadrau for some miles south, 

 wards, but they do not form anything like so marked a feature 

 as they do in the eastern jDortion of the island. 



Some distance north of Waisa there is what appears to lie a 

 dyke of andesite 20 feet wide, cut through the tuffs. This dyke (?j 

 is not straight, but forms about a quadrant of a circle whose 

 chord is about east and west. The diameter of the circle is about 

 half a mile. 



From this point to the large town of Waisa the tuff beds are 

 again fine-grained, and almost level, the general dip being about 

 N.X.E. at 3° to 7'. Just north of the town (Waisa) there is a 

 patch of tuffaceous conglomerate containing rounded boulders of 

 andesite (Plate xxxii., fig. 16). 



South of the town the character of the country changes. The 

 place of the friable, level, and recent-looking tuffs is taken by 

 hard greenish-looking tuffs, highly jointed and with obscure dips 

 at high angles. These give place here and there to the recent 

 .soft tuffs. 



About six miles south of Waisa, an afiluent called the Nakabi 

 enters the Sigatoka from the east. Amongst the gravels are a 

 few well-worn pebbles of granite, but from the fineness of most 

 of the material and the comparative scarcity of pebbles, it is 



