TAHITI. 143 



the position of the former extension of spurs of the mainland, of which they 

 are the only outliers left (PI. 208, fig. 3). 



At Taunoa the reef flat again becomes a fringing reef flat ; the entrance 

 to Phaeton Harbor is flanked on the two sides by gigantic reef flats (PI. 208, 

 fig. 1), the northern one of which is a fringing reef flat, while the southern 

 is a wide flat separated from the mainland by a lagoon from ten to fifteen 

 fathoms deep. The lagoon extends along- the western and the southwestern 

 shores of Taiarapu Peninsula, as far as Tutataroa Pass (PI. 208, fig. 1), with 

 here and there a pass connecting it with the sea. Beyond Fareai'a Point the 

 extension of this reef flat, as it skirts the southeastern extremity of the pe- 

 ninsula, becomes a submerged flat (PI. 208, fig. 1), covered with from two 

 to eleven fathoms of water. The reef flat has been eroded and forms 

 only an indistinct bar across the face of a broad lagoon, extending from 

 Tutataroa Pass to Tomotai Pass (PI. 208, fig. 1). The eastern and northern 

 face of Taiarapu Peninsula is flanked by disconnected reaches of narrow 

 barrier reefs separated by deep passes. From Tiitau to Papeivi Pass across 

 Taravoa Bay the narrow barrier reef has been greatly eroded, and only here 

 and there an isolated rocky islet is left. Some of the patches and stretches 

 between the narrow barrier reefs of the eastern side of Tahiti have also been 

 planed off by submarine erosion into submerged reefs (PL 208, fig. 2), similar 

 to those off Fareara Point. 



A very striking feature of Tahiti is the number of watercourses which 

 flow from the centre of the island towards the shore (PI. 202, fig. 1). The 

 high steep slopes and bluffs which fringe the island are cut by innumerable 

 deep valleys penetrating almost to the centre (Pis. 86, fig. 2 ; 88, fig. 1 ; 

 89, fig. 1). The only locality where a gradual slope extends toward 

 the sea is between Paea and Punaavia (PI. 85),^ where the slopes rise 

 gradually to the summit of Mount Taiti to a height of over 4500 feet. The 

 valleys radiating from the central part of the island all bring down to 

 the coast an immense amount of fresh water. On the eastern face nimierous 

 waterfalls are seen, many of them falling from great heights. The amount 

 of water which has thus found its way into the lagoons accounts in great 

 part for the exceedingly rotten condition of the coral mass which forms the 



1 A. Chart X382. 



