AGASSIZ: FIJI ISLANDS AXD CORAL EEEFS. 61 



end of Ongea Levu the lagoon expands, and attains a width of neai-ly 

 six miles. The onter reef flat is narrow, but expands to a width of 

 three quarters of a mile off the southern face of Ongea Ndriti, where 

 it becomes a fringing reef. Ongea Xdriti is nearly two miles long 

 and one mile broad, and rises to a height of 300 feet. The Barracouta 

 Passage is the only ship channel leading into the lagoon. It opens 

 tlu'ough the western reef flat into the widest part of tlie pear-shaped 

 lagoon, a little south of the extremity of Ongea Levu. The greatest 

 length of the lagoon is about eig-ht miles. 



The Ongea Islands consist of elevated limestone, rising in nearly verti- 

 cal cliffs along the shore line. This is deeply indented by broad and deep 

 bays, forming small irregularly shaped sounds, which in the case of Ongea 

 Levu have nearly cut that island into two (Plate 22). The openings of 

 the bavs and the shores of the islands themselves on the western and 



!» 



SOUTinVEST POINT OF ONGEA LEVU. 



southei'n faces of Ongea Levu are studded with islets and I'ocks, whicli, 

 like the ridges of the islands, consist of elevated limestone. They are 

 most numerous off the wide and deep bay on tlie southern face of the 

 larger island, and extend across the channel separating Ongea Levu and 

 Ongea Xdriti (Plate 94). The outliers extending south from the former 

 island connect with those stretching north from the opposite face of the 

 smaller island. 



The mushroom-shaped rocks and islets also extend along tlie western 

 face of Ongea Ndriti, but they are not as numerous as on the northern 

 fixce. On many of the islets are found a few straggling palmettos, iden- 

 tical with those growing on the principal island. The islets and rocks 

 as well as the shoi'e cliffs are deeply undercut, and the surface is deeply 

 pitted, honeycombed, and full of potholes and caverns, and presenting 

 the appearance so characteristic of the weathered coralliferous limestone 

 wherever we have found it in Fiji. It seems, however, as if the erosion 



