ANDREWS : LIMESTONES OF THE FIJI ISLANDS. 9 



blocks belong to the raised limestone, and not to the older "bedded 

 limestones," which latter are largely foraminiferal. 



(b) Massive flows of andesite like those of Mount Rupert in Mango. 

 These cap the coral agglomerates (a) ; they have a very fresh appear- 

 ance, are in no places capped or encrusted by the raised limestone, and 

 invest the raised limestone and enclose inliers of it. For these reasons 

 Mr. Andrews considers these andesites newer than the preceding agglom- 

 erate and than the raised limestone. 



These lavas rise in dome-shaped masses to a height of 700 feet above 

 the sea, and attain a thickness of about 300 feet. 



6. Basalts. These form small outcrops quite inconspicuous as com- 

 pared with the andesites. 



They are olivine basalts, having a very fresh appearance, and Mr. 

 Andrews considers them to be of later origin than the andesites, and 

 consequently the newest of the volcanic rocks of Fiji. 



7. The pi'esent coral reefs. As regards the origin of the raised lime- 

 stones of the Lau Group, it would, of course, be premature to advance 

 any definite conclusions pending the examination of the collections made 

 by yourselves and by Mr. Andrews. 



At the same time, a brief statement might be made here as to Mr. 

 Andrews' present opinion about them and my opinion as to their relation to 

 the limestone penetrated to a depth of 1114 feet in the bore at Funafuti 

 Atoll, Ellice Group. Such thin bands of the limestone rock from Lau 

 as Mr. Andrews classes as true raised coral reef seem to me very closely 

 allied to the bulk of the rock penetrated at Funafuti. Mr. Andrews con- 

 curs in this opinion. In the Lau Group, however, such true raised coral 

 reefs proper, in Mr. Andrews' opinion, form only a very small proportion 

 of the whole thickness of raised limestone. At Funafuti, however, they 

 constitute by far the greater proportion of the whole thickness of rock 

 proved in the bore. Whereas, then, at Funafuti, in my opinion, there is 

 little calcareous rock that is not true reef, at Lau, in Mr. Andrews' 

 opinion, there is little visible calcareous rock that is true reef. Mr. 

 Andrews thinks that probably the raised limestones of Lau acquired 

 their great thickness of over 800 feet by outgrowths of coral reef on a 

 bank of coral talus and foraminiferal nullipore limestone during a long 

 period of crustal quiescence followed by intermittent upheavals with 

 several intervening periods of quiescence which led to the formation 

 of the terraces. 



Most of the raised limestone reefs of Lau are distinctly raised atolls, 

 notably Tuvutha, of which the old lagoon floor is about 350 to 400 feet 



