140 -'ALBATROSS" TROPICAL PACIFIC EXPEDITION. 



The vegetation of the Society Islands is already far more luxuriant 

 than that of the Paumotus more to the eastward. This we might expect 

 from the greater size of the islands, the more varied climatic conditions, and 

 the greater fertility of the soil. Even on the coral sand islets on the outer 

 edge of the barrier reef flats, the vegetation is far more varied and luxuriant 

 than on the similar islands and islets of the land rim of the Paumotus. Les- 

 son gives a list of a large number of genera which do not occur east of 

 Tahiti, but which are still better represented as we pass to the westward, to 

 Samoa, to the Tongas, the Fijis, and the Carolines. 



Mehetia. 



Plates 90, fig. 2 ; 95, fig. 1 ; 202. 



Mehetia, the easternmost of the Society Islands (PI. 202), is an isolated 

 volcanic peak nearly 1600 feet in height, with a couple of rocky islets and 

 rocks off the southern point. On the eastern and southern faces the slopes 

 of the island have been abruptly cut off, and terminate in vertical cliffs 

 and columnar masses of basalt at the base of the slope, on the northeastern 

 face of the island. A few corals have been thrown up on the small beaches 

 of the island along the east face and near the northeast point. 



On the western face considerable coral sand has been thrown up on the 

 western point of the island, derived from the few coral patches which are 

 formed on the flat, the seaward extension of the western point (PI. 95, 

 fig. 1). 



On the summit of the island a well-marked crater exists. It is best seen 

 when facing the island from the north (PI. 90, fig. 2). It is interesting 

 to find a volcanic island like Mehetia, situated in the belt of the trades, 

 on which cor.als have taken no such development as they have on the 

 other vulcanic islands of the group. As I have stated, there are no coral 

 reefs around the island, only a few coral patches, and the only difference 

 we notice in the structure of Mehetia and of the Marquesas is the absence 

 of a .shore platform on which either fringing or barrier reefs can develop. 



The absence of a shore platform on Mehetia and the Marquesas is prob- 

 ably due to the steepness of the slopes, which, when cut into, do not form 



