148 "ALBATROSS" TROPICAL PACIFIC EXPEDITION. 



side. It is probable that these passes have, to a certain extent, been 

 formed by the action of the silt, which is brought down b}' the fresh water 

 flowing into the lagoon and which has killed the corals lying in their 

 path. The strength of the currents is also due, in great part, to the 

 amount of water which is forced over the sea face of the reef flats by the 

 incessant roll of the breakers. Even on the faces of the island where 

 the sea does not strike directly on the land, as on the west side, during 

 the prevalence of the southeast trade, there is a constant swell running in, 

 either from the north or south or west, which pours volumes of water over 

 the outer edge of the reef flat. The strength of the currents which sweep 

 out through the passes depends entirely upon the direction of the wind, 

 the prevalence of the swell, and the season of the year. The coast shelf 

 varies greatly in width, being indistinct, as we have stated, to the north of 

 Paea and comparatively narrow from Paea to Papara, where the steep 

 cliffs rise more than two thousand feet and slope directly to the shore ; the 

 shore flats widen out again to the east of Popote Bay, and form deep 

 indentations on the south and west coasts of Taiarapu Peninsula, The 

 eastern and northern coasts of the peninsula are flanked by steep blufts 

 rising almost vertically from the sea, to a height varying between twelve 

 and fifteen hundred feet, with deep vallej^s reaching- far into the interior 

 of the peninsula. The Isthmus of Taravao itself forms a broad, low gap 

 sloping towards the interior of the main island and the peninsula. From 

 north of the isthmus the scenery of the island is, perhaps, finer than in 

 any part of Tahiti (PI. 86, fig. 2). Numerous waterfalls fall from great 

 heights, into the deep gorges, which have been cut towards the centre 

 of the island ; endless furrows forming sharp spurs and ridges divide this 

 slope into naiTOW valleys, opening on the coast of the main island. On the 

 northern face of the island the slopes are moi'e gentle, and off Point Venus 

 one can look far into the interior of the island np the broader valleys of 

 that part of the coast. 



The extent of the erosion and denudation of Tahiti is well shown by the 

 many directions from which " Le Diademe " can be seen from the sea, as off 

 Point Venus on the north coast, off Tuaura Valley and off the east coast, off 

 Artemise Bank, positions which are almost at right angles to one another. 



