GEOTvOGlCAL OBSEKVATIOXS IN' FIJI. 



Page. 



Figure 29. Profiles of Ndoi, Ono-i-laii 62 



Figure 30. View of Ndui from Oiio Lovu 03 



Figure 31. Sketch Map of the Ishmds of Kamhara, Wangava and 



Maranibo ()6 



Figure 32. Sketch Maj) and Profile of Ndelai Yaloi, Kambara ... 67 



Figure 33. Profile of \\angava as seen from Kambara 70 



Figure 34. Sketch Map and Profile of Ongea 71 



Figure 35. East-West and North-South Profiles of Vatoa .... 72 



Figure 36. Typical Cross-section of a Barrier Reef 73 



Figure 37. Sketch Map of Fulanga 74 



Figure 38. Hachure Map and Profile of Munia, I'kploring Group . 78 



Figure 39. View of Mhengha as seen from the Northeast .... 80 

 Figure 40. Cross-section of Elevated Limestones near the Village of 



Kandavu, Kandavu 83 



INTRODUCTION. 



The difficulty of finding conclusive evidence concerning the nature 

 of the foundations on which aoral reefs stand has led to prolonged dis- 

 cussion of the coral reef problem. During this discussion Darwin's 

 theory of the origin of atolls has been the storm center. 



The earlier investigators studied the reefs with little reference to 

 the adjacent lands. Among them, Dana (1853, p. 118) alone saw that 

 the reef and the land form back of the reef were intimately connected ; 

 that the history of one was written, in part, in the outline of the other. 

 In the last few years, W. M. Davis has emphasized the importance 

 of embayed shorelines behind barrier reefs. The abundance of these 

 features, which Darwin neglected in the announcement of his theory, 

 and the numerous cases of coralliferous limestone resting unconform- 

 ably on eroded rocks, has led Davis to believe that Darwin's theory 

 is correct. 



A luxuriant tropical vegetation has rendered it often difficult to 

 determine the structure of the upraised coral limestones and the nature 

 of their contact with the underlying rocks. It is evident that such 

 data are very important to the coral reef problem. For example, the 

 structure of a reef which develops on an outward-growing platform 

 of its own debris during a stillstand of the ocean level, as postulated 

 by Sir John Murray (1880, p. 517), will not be the same as that of 

 a reef formed on a subsiding volcanic mass, according to Darwin's 

 theory. 



With the hope that the study of the structure of the central 



