Soil Sequences in Hawaii — Sherman and Ikawa 
461 
turn overlies an un weathered volcanic ash. The 
difference between the groups is largely in the 
degree of removal of bases by leaching and the 
increased content of free oxide. Generally, soils 
of the Low Humic Latosol and Ferruginous 
Humic Latosol occur on the older islands in 
areas of similar environmental conditions, but 
do not occur on the younger islands. The work 
of Tamura et al. (1955) supported the hypoth- 
esis that the soils of the Latosolic Brown Forest 
were the precursors of the Ferruginous Humic 
Latosol. This conclusion was based on similari- 
ties in mineral composition of soils of the Naiwa 
family of the Ferruginous Humic Latosol group 
of West Maui, and the soils of the Olinda 
family of the Latosolic Brown Forest group of 
East Maui. The similarities between the soils of 
the Reddish Prairie group and soils of the Low 
Humic Latosol group are even greater. 
An attempt has been made to study the 
changes made by weathering in soils of the 
same type from different areas, but formed un- 
der the same climatic environment and from 
very similar parent materials. Field observations 
indicated that a Lahaina soil developed on the 
Waimea volcanic series of Kauai (the oldest 
flows of the Hawaiian Islands) showed mor- 
phological properties suggesting a greater de- 
composition of clay minerals than was normal 
for these soils, which are made up predomin- 
antly of kaolin clays. Chemical analyses of 
samples of soil of this profile were compared 
with the analysis of a soil belonging to the 
Lahaina family formed under almost identical 
conditions but from Molokai, a younger island. 
The results of these analyses are given in Table 
2, for the younger Lahaina soil, and in Table 3 
for the older Lahaina soil. A comparison of the 
data reveals that the older soil has lost more 
silica, calcium, and magnesium than has the 
younger. The higher content of titanium and 
iron oxides in the surface horizon of the older 
Lahaina soil would suggest that the process of 
weathering is slowly converting this soil to one 
having the characteristics of the Ferruginous 
Humic Latosol group. Further evidence of the 
greater desilication in the geologically older 
profile is shown in the molecular ratios of Si0 2 
to R 2 0 3 , which range from 0.84 to 1.14 in the 
older profile to 1.36 to 1.87 in the younger pro- 
file. Likewise, the ratio of Si0 2 to Al 2 0 3 was 
consistently lower in the older profile. The ratio 
of Si0 2 to Fe 2 0 3 was lower in the older profile 
and also much lower in the surface horizon. 
This soil must be considered at least an inter- 
grade to the Ferruginous Latosols. 
TABLE 2 
Chemical 
Composition of 
a Soil of the Lahaina Family from the 
Moderate Age of Weathering 
Island 
of Molokai; 
CHEMICAL 
CONSTITUENT, 
PER CENT 
horizons in inches 
0-3 
3-15 
15-35 
35-46 
46-60 
Si 0 2 
31.23 
32.23 
32.36 
32.73 
40.80 
•^ 2® 3 
23.84 
23.76 
24.85 
26.30 
25.61 
Fe 2 G 3 
23.29 
23.96 
23.40 
23.46 
17.84 
TiO s 
4.90 
5.78 
5.81 
4.61 
3.74 
MnO 
0.30 
0.30 
0.22 
0.19 
0.28 
CaO 
0.76 
0.58 
0.72 
0.43 
0.71 
MgO 
0.51 
0.45 
0.43 
0.39 
0.62 
k 2 o 
0.20 
0.13 
0.13 
0.05 
0.07 
Na 2 0 
0.03 
0.06 
0.03 
0.08 
0.06 
PH 
K — 
Si0 2 
R 2G 3 
K = 
Si0 2 
ai 2 o 3 
TV _ 
Si0 2 
Fe 2 0 3 
6.2 
6.2 
5.2 
4.9 
— 
1.36 
1.40 
1.38 
1.35 
1.87 
2.21 
2.30 
2.21 
2.12 
2.71 
3.57 
3.58 
3.70 
3.71 
6.07 
