A number of surface soil samples were taken and will be reported 
on elsewhere. The soils found on the island are typically sand 
based with additions of varying amounts of organic material of 
two types, bird guano and decayed vegetable material much of which 
is processed/by the hermit crabs. Much of the inner slopes - the 
wider found on the west side — are covered to a depth of several 
dm. with a sandy soil ev e glyi-ag which overlays wave deposi tod 
coral rubble. Many areas on the IT and S sides which are more recent 
deposits judging from the lack of soil cover have pockets of sand 
but these are often too far from the surface to provide a habitat 
for plants. In other areas coral waverows have been filled with 
wind and wave deposited sand and on which pione er plant species 
such as Boerhavia and Portulaea find a niche. Often these waverows 
become obscured by the deposition of sand and the formation of soil 
subsequent to the formation of plant communities. The soils range 
from almost pure sand to those which contain a letf degree of organic 
material. In some small sites such as thick stands of lepturns, under 
Tournefortia and Cordia groves and in locally more mesie sites with 
y* 
lusher vegetation one will finds feir correspondingly higher amounts 
of organic material mixed with the sand. A second type oi soil xs 
found in the low, former lagoon flats and present lagoon with its 
numerous islets. On the flats one finds a reddish brown, friable 
soil derived from guano accumulations of nesting seabirds. At the 
dry edges of the present lagoon a highly saline soil also with admix¬ 
tures of guano is found. On the dry islets a lighter powdery guano 
soil with an admixture of salie and ..calcium.carbonates derived from 
exposed fossil layers of mollusks which inhabited the old lagoon, is 
found. On this soil type are found Sesuvium and Bragrostis and sparingly 
Portulaoa lutea, Sida fallax and Lepturus . At perhaps a half m. elevation 
gaietythese low guano soil area one finds Portulaoa as a common 
component of partially guano filled soils. It may be that with the 
lowering of the flats due to the guano mining tiiat '■ he areas for optimal 
growth of the Sesuvium — Bragrostis association were increased to the 
detriment of that area on which was iound at an. elevation only perhaps 
a half meter higher the Portulaoa - Leuturus association which may 
have characterised much of the guano filled areas of the dry central 
Pacific atolls. 
The concentric pattern of atoll vegetation can he seen on Bnderbuxy 
