462 
PACIFIC SCIENCE, Vol. XXII, October 1968 
TABLE 3 
Chemical Composition of a Soil of the Lahaina Family of the Low Humic Latosol from 
Kokee Road, Kauai; Exposed to Weathering for a Long Geologic Period 
CHEMICAL 
CONSTITUENT, 
HORIZONS IN INCHES 
PER CENT 
0-9 
9-14 
14-18 
18-40 
40-48 
48-65 
65-75 
Si0 2 
21.08 
25.56 
27.84 
28.04 
29.06 
29.40 
29.44 
ai 2 o 3 
20.64 
25.68 
28.88 
31.04 
29.20 
29.60 
29.28 
Fe 9 G 3 
34.63 
27.26 
22.42 
21.73 
23.83 
22.22 
23.86 
Ti6 2 
10.41 
5.48 
3.22 
3.27 
4.92 
4.06 
4.94 
MnO 
0.24 
0.22 
0.20 
0.20 
0.21 
0.20 
0.24 
CaO 
0.09 
0.06 
0.03 
0.03 
0.02 
0.02 
0.02 
MgO 
0.96 
0.66 
0.49 
0.53 
0.54 
0.57 
0.58 
k 2 ° 
0.02 
0.11 
0.22 
0.19 
0.07 
0.10 
0.07 
Na 2 0 
0.14 
0.43 
0.47 
0.56 
0.54 
0.58 
0.55 
pH 
4.9 
4.9 
4.8 
4.8 
4.8 
4.6 
4.5 
SiOo 
K = 
0.84 
1.01 
1.10 
1.06 
1.11 
1.14 
1.13 
^2^3 
Si0 2 
K = — 1.74 1.70 1.64 1.54 1.69 1.69 1.71 
A1 2°3 
Si0 2 
K= 1.63 2.49 3.31 3.43 3.25 3.53 3.29 
Fe 2 0 3 
The chemical and mineralogical changes oc- 
curring in the profile of the older Lahaina soil 
support the hypothesis of sequence of soil for- 
mation presented by Sherman in 1949. In this 
hypothesis, it was proposed that the kaolin soils 
of the Low Humic Latosols would lose their 
bases and would slowly desilicate with geolog- 
ical age and gradually acquire the characteristics 
of soils of the Ferruginous Latosols. 
SEQUENCE OF ROCK WEATHERING 
A study of progressive rock weathering as it 
is related to the origin of the parent material 
TABLE 4 
Chemical Composition of Ultrabasic Basalt Rocks and the 
Soil Weathered from Them Under Different Rainfalls 
(the Soil Sample in Each Case is 2 Inches from Rock) 
Si0 2 
ai 2 o 3 
^ e 2^3 
TiO, 
LOSS ON 
IGNITION 
SAMPLE DESCRIPTION 
% 
% 
% 
% 
% 
A. From Low Humic Latosol, Kapaa, Kauai — 45 inch rainfall 
Rock core 42.4 14.9 14.8 2.1 1.6 
Weathered soil 25.9 24.5 30.0 4.7 10.6 
B. From transition zone between Ferruginous and Low Humic Latosol groups, 2 miles west of Kapaa, Kauai — 
60 inch rainfall 
Rock core 42.9 14.6 14.6 2.0 1.3 
Weathered soil 24.8 29.0 30.0 4.2 12.1 
C. From Ferruginous Latosol, Wailua Homestead, Kauai — 90 inch rainfall 
Rock core 45.8 16.2 14.9 2.5 2.5 
Weathered soil 18.5 32.2 29.6 5.2 14.4 
D. From Ferruginous-Aluminous Latosol, Wailua Game Refuge, Kauai — 120 inch rainfall 
Rock core 36.7 10.8 14.2 2.8 — 
Weathered soil 2.4 39.3 36.5 6.5 16.7 
