Soils of Palau — VESSEL AND SlMONSOM 
293 
gest that these soils lean somewhat in their 
characteristics toward the Davidson series. 
Hence, they seem to be intermediate between 
modal profiles for the Latosol group and the 
Reddish-Brown Lateritic soils. 
The morphology and composition of the 
b auxin c Latosols in the Palau Islands indicate 
that they are more strongly weathered than 
the Humic Latosols and more nearly com- 
parable in this respect to the Humic Fer- 
ruginous Latosols of Hawaii. Sesquioxides 
have been concentrated to a high degree, 
partly in the form of concretions, in the 
bauxitic profiles (Table 2). Compared to the 
Haiku and Naiwa series in Hawaii (Cline et 
al 1939), the bauxitic profile is much lower 
in Si0 2 and Ti0 2 , somewhat lower in Fe 2 0 3 , 
and much higher in Al 2 0 3 . It is comparable 
in contents of SiO a and TiO s , lower in 
Fe 2 0 3 , and higher in Al 2 O s than the profiles 
of Nipe clay described by Marbut (1930). 
Thus the concentration of sesquioxides, con- 
sidering both aluminum and iron, is compar- 
able in the bauxitic Latosol to that of Humic 
Ferruginous Latosols of Hawaii and to the 
Laterite soils of Cuba and Puerto Rico. The 
chemical and mineralogical composition of 
the bauxitic profiles as indicated in Tables 1 
and 2 suggests that it is one of the end prod- 
ucts of soil formation in the humid tropics. 
The Latosols of the Palau Islands clearly 
represent two subdivisions of the broad group 
or suborder. The bauxitic soils are examples 
of a strongly weathered group similar in many 
ways to the Nipe clay of Cuba and Puerto 
Rico and to the Humic Ferruginous Latosols 
of Hawaii. On the other hand, the profiles low 
or lacking in concretions in the Palau Islands 
resemble the Humic Latosols of Hawaii in 
some ways and the Low Humic Latosols in 
others. It may be that they should be con- 
sidered comparable to Humic Latosols in the 
drier part of their climatic range. Dominant 
Latosols of the Palau Islands also seem to 
have a few properties in common with the 
Reddish-Brown Lateritic group of the south- 
eastern United States. 
Regosols , Alluvial Soils , and Organic Soils 
These soils comprise about 6 per cent of 
the total land area of the Palaus but produce 
most of the food in the present agriculture. 
The one Regosol is a soil type widespread on 
Pacific islands, known as Shioya sand. The 
Alluvial Soils are moderately fine-textured 
and predominantly poorly drained, though 
they have a wide range in drainage conditions. 
Organic Soils consist of peats and mucks. The 
Alluvial Soils are slightly more extensive than 
either Shioya sand or the Organic Soils. 
1. Shioya Sand 
This soil type occupies raised beaches or 
low coastal terraces that are above wave ac- 
tion, principally in north Peleliu and at the 
north and south ends of Angaur. Additional 
areas too small to be shown in Figure 2 occur 
along the northeastern coast of Babelthuap 
and along the shores of Peleliu. Total area of 
Shioya sand in the islands is 2.7 square miles. 
The profile of Shioya sand consists of a 
thin (2-3 inches) gray (2.5Y 5/1) or grayish 
brown (10YR 5/2) Ai horizon over a light 
gray (2.5Y 7/2) C horizon. The whole profile 
consists of sand or fine sand, which may be 
replaced by gravel at depths of 2 to 4 feet. 
In most places, some coral fragments occur 
on the surface and throughout the profile. 
Consisting largely of coralline limestone frag- 
ments, Shioya sand is strongly calcareous. 
Much of the total area of Shioya sand has 
been planted to coconut palms, for which the 
soil is well suited. Minor crops that seem to 
grow well are lemons, bananas, papayas, and 
breadfruit. 
2. Alluvial Soils 
These soils occur along most streams and 
along many of the upland drainageways in 
the Palau Islands. Only the areas along the 
lower courses of principal streams can be 
shown, however, in Figure 2. The soils are all 
slightly acid in reaction, and the dominant 
ones are poorly drained. Less extensive are the 
well-drained soils and those intermediate in 
