UADACK A.VD OTHER ISLANDS. 145 



side, a thin layer; the formation seems to be new, 

 and layers of sand mostly alternate with those of 

 limestone. This is always the case on the beach 

 of the inner sea. 



A dam of great madrepore-rolls cast up upon 

 this foundation, forms, towards the breakers, the 

 exterior edge of the islands. The interior of them 

 consists of flats and small hills. Towards the beach 

 of the inner sea, the ground is raised a little, and 

 of fine sand. On the island of Otdia, in the group 

 of the same name, the inner sea encroaches on the 

 land in one place, and a Lyihrum Pemphis grows 

 with bare roots on the rocks which are washed by 

 the sea. In the inner part of Otdia there is a lake 

 of sweet water, and in Tabual, of the group of Aur, 

 a marshy ground. There is no want of fiesh 

 water in the larger islands ; it rises sufficiently in 

 the pits dug for the purpose. 



On the dam of fragments wliich surrounds the 

 exterior of the islands, grow, first, Scaevola Konigii 

 and Touniefortia sericea. These screening bushes 

 gradually rise, and their thickly intertwined 

 branches present outwardly to the wind an inclined 

 surface, under the protection of which the wood or 

 bushes of the interior of the island rises. The Pmi' 

 danuSy and where the soil is richer, also a Cerhera 

 constitute the chief vegetation. Guettarda speciosa^ 

 Morinda cilrifoliay Terminalia Mobiccensis, are 

 common on all the islands. Hernandia sonora is 

 seldom wanting on the richer ones j C(dophyUum 



VOL. III. L 



