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The remainder have solums which are less 
than 1 foot thick. Colors range from low 
chromas and values of 10R hue to rather high 
figures of 7.5YR hue. The bulk of the soils 
have colors of 2.5YR and 5YR hues. Some 
profiles have appreciable numbers of concre- 
tions of various sizes in and on the surface 
layer. Concretions may be common but not 
numerous. Thickness of the Regolith in which 
the soils are formed is generally great, com- 
monly falling between 40 and 100 feet. 
Minor components of this association, the 
Alluvial Soils and Regosols or regosolic soils, 
form 10 to 15 per cent of its total area. The 
Alluvial Soils are similar to those in other 
associations dominated by Latosols. The Reg- 
osols or regosolic soils are restricted to the 
steepest slopes and have about the same total 
area as Alluvial Soils. The Regosols or rego- 
solic soils may have faint A horizons or may 
consist entirely of weathered Tuffs. 
4. Latosolic Soils from Clays (Ngatpang 
Association and Tabagaten Association) 
Two soil groups are the main components 
of this association, all of which are derived 
from sedimentary clay beds. The more ex- 
tensive group consists of Red- Yellow Pod- 
zolic soils which approach Planosols in fine 
texture and low permeability of the B horizon. 
They resemble the Colbert series formed from 
argillaceous limestones in the southeastern 
United States. The B horizons are mainly 
yellowish-brown (10YR hue) silty clays. The 
second major group in the association con- 
sists of yellowish-red to red soils which seem 
to be intermediate in character between Lato- 
sols and Red-Yellow Podzolic soils. They 
have some of the properties of each. They 
may be more nearly related to the Davidson, 
Decatur, and similar series than to typical 
Latosols or Red- Yellow Podzolic soils. All 
gradations in profile exist between the yel- 
lowish-brown and red components of this 
association. 
Minor components of the association are 
Low Humic-Gley soils, Alluvial Soils, and 
Regosols, which collectively comprise about 
20 per cent of its total area. Low Humic-Gley 
soils occur in smooth uplands and on the 
lower parts of long slopes. Alluvial Soils are 
found along drainageways. The Regosols 
occupy the rare steep slopes. 
Restricted in its occurrence on Babelthuap, 
this association has a total area of about 5 
square miles. The main bodies are in the west 
central part of the island, with a few small 
ones near the southern end. 
Topography is dominantly undulating to 
rolling, in contrast to the hilliness of the Lato- 
sols from Breccias and Tuffs. Slopes are long 
and gentle. Local relief is measurable in feet 
as a rule though it may reach tens of feet in a 
few places. Latosolic soils from clays com- 
prise the smoothest uplands on Babelthuap. 
5. Chemical and Mineralogical Data on 
Profiles 
Certain laboratory analyses have been made 
on samples of the major horizons of several 
profiles from the Palau Islands. Data obtained 
will be given in full in a later publication, but 
a few are given here to complement the 
morphological observations. Table 1 gives 
data for exchangeable cations, pH, exchange 
capacity, base saturation, and organic matter 
for three profiles which represent the domi- 
nant Latosols of the islands. Table 2 gives 
data on chemical and mineralogical compo- 
sition on a section sampled for the study of 
bauxite ore in an area of bauxitic Latosols. 
The laboratory analyses reported in Table 1 
were made in the Department of Soils and 
Agricultural Chemistry, University of Hawaii, 
and in the Soil Survey Laboratories, SCS, 
U. S. Department of Agriculture. Methods 
used at the University of Hawaii are described 
by Piper (1944), whereas those used in the 
Soil Survey Laboratories are described in U. S. 
Department of Agriculture Circular 757 (Peech 
et'al.y 1947). 
Data given in Table 2 are from the labora- 
tories of the U. S. Geological Survey. Stand- 
ard methods for chemical analysis were used 
