276 
PACIFIC SCIENCE, VoL VII, July, 1953 
TABLE 3. 
Chemical Analyses of the Fine Fraction ( < 0.002 mm.) of 
Representative Saipan Soils (after Kawamura et al.) 
SOIL TYPE 
sample 
DEPTHS 
Si02 
AI2O3 
Fe203 
si02 
AI2O3 
si02 
R2O3 
Inches 
Per cent 
Per cent 
Per cent 
MoL Ratio 
MoL Ratio 
"Red-colored limestone soil” 
= Saipan clay 
0- 6 
23.53 
34.79 
15.77 
1.15 
0.89 
6-45 
25.91 
40.56 
10.35 
1.08 
0.93 
"Yellow-colored limestone 
soil” = Chacha clay 
0- 8 
33.99 
43.21 
15.36 
1.33 
1.09 
8-22 
37.50 
36.37 
8.77 
1.74 
1.51 
22 + 
40.70 
38.78 
6.52 
1.78 
1.58 
"Brown-colored limestone 
soil” = Dandan clay loam. . . 
0-10 
15.09 
40.05 
10.81 
0.64 
0.54 
10-33 
12.25 
43.30 
13.91 
0.48 
0.40 
"Red andesitic soil” 
= Dago clay 
0-12 
33.90 
33.24 
11.32 
1.73 
1.42 
12-50 
36.32 
33.39 
13.27 
1.84 
1.47 
"Red tuffaceous soil” 
= Akina clay 
0- 8 
49.37 
25.96 
11.15 
3.20 
2.51 
8-24 
45.98 
27.92 
7.96 
2.66 
2.25 
24 -f 
42.59 
28.06 
11.34 
2.58 
2.05 
Fractionation was obtained by the pipette method. 
of 4 feet or more. A highly variegated red, 
yellow, and white strongly acid clay of vary- 
ing consistence extends to depths of 15 feet 
and more, below which are unaltered volcanic 
tuffs, flow-rocks, and sediments of volcanic 
origin (profile diagram, Fig. 1). Chemical data 
of Kawamura (Tables 1, 2, 3) for samples 
apparently correlating with this soil series in- 
dicate about 35 per cent silica in the fine 
fraction of the subsoil. Cation exchange ca- 
pacity of 12 milliequivalents per 100 grams of 
dry soil and a derived silica-sesquioxide ratio 
of about 1.45 for the subsoil are reported. 
These deep soils underlaid by volcanic 
rocks do not fully qualify as latosols on the 
basis of their morphological and chemical 
properties, as described above. One would 
expect to find latosols, as environmental con- 
ditions of year-round high temperatures and 
moderately annual rainfall are similar to other 
parts of the world where latosols have been 
described as developed over volcanic rocks. 
Examples are the Flawaiian Islands, where 
latosols have been described by Cline (manu- 
script) and chemical data presented by Hough 
and Gile (1941), and the soils of the Belgian 
Congo described by Kellogg and Davol 
( 1949 ). However, the Cialitos soils of Puerto 
Rico as described by Roberts et aL (1942) 
seem to be similar to the Akina and Dago 
soils in properties and environment and were 
classified as "Reddish Brown Lateritic.” The 
tuffaceous shales and volcanic rocks described 
as the parent material of this Puerto Rican 
soil may, however, have had some extreme 
effects on its direction of development. 
As the deep soils of Saipan underlaid by 
volcanic rocks more closely resemble latosols 
than any other class at present defined, it is 
proposed also to term them "latosolic inter- 
grades.” This signifies that their properties 
are in a range between those of a modal latosol 
and some other class or classes not at present 
defined. More precise definition of classes of 
tropical soils in the higher categorical levels 
of classification and more laboratory analyses 
of Saipan soils are necessary before any fur- 
ther statements on their classification and 1 
correlation can be made. i 
