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Each pit was dug to a depth of 2 m. The soil 
horizons were described as to depth, material, 
and color, and samples were collected for lab- 
oratory analysis. The soil samples included three 
sets, one for microbiological analyses (now be- 
ing conducted), one for current soil moisture 
analysis, and one for other soil tests. In addi- 
tion, the three soil profiles were prepared as soil 
monoliths after the method of Smith and 
Moodie (1947) for further mega- and micro- 
scopic inspection and as permanent records. 
Subsequent soil tests carried out included 
determination of moisture equivalents (by the 
centrifuge method), permanent wilting per- 
centages (by the sunflower method), organic 
carbon (by the Walkley-Black wct-combustion 
method), and pH (by electric pH meter). 
Herbarium specimens were prepared. One set 
has been deposited in the herbarium of the 
University of Hawaii, and a second set in the 
herbarium of Hawaii Volcanoes National Park. 
RESULTS AND DISCUSSION 
A. Soils 
The soils give convincing evidence that they 
have been derived from volcanic ash and not 
from old, disintegrated lava as has been as- 
sumed by the authors who published the nature 
trail guide for Kipuka Puaulu (1961 edition). 
Ash strata were found to the depth of 2 m to 
which all soil pits were dug and there was no 
sign of parent material change at this depth. 
Rock (undated) indicated that the soil in K - 
puka Puaulu was nearly 6 m deep. The maxi- 
mum soil depth in Kipuka Ki is not known. 
Ash was deposited not at one time but in 
several stages, probably extending over many 
hundreds of years. Corresponding ash layers 
that appear to have originated from the same 
eruptions can be found in all soils we examined. 
Noteworthy are two thin red pumice layers that 
occur in each soil. One occurs in the lower pro- 
file at 100 cm depth in the soil of Kipuka Ki, 
at 140 cm in the forest soil of Kipuka Puaulu, 
and at 145 cm in the savannah soil (Fig. 2). 
A second red pumice layer is found in all soils 
nearer the surface, at 60 cm in Kipuka Ki, at 
70 cm in the forest soil of Kipuka Puaulu, and 
at 85 cm in the savannah soil. 
PACIFIC SCIENCE, Vol. XXI, April 1967 
Ash deposits were composed of at least five 
different materials: a fine, dusty gray ash with 
scattered pebbles up to 5 mm in diameter, a 
gravelly ash with basaltic and variously vesicular 
pebbles up to 1 cm in diameter, a black vitreous 
ash, a yellow-olive pumice, and the red pumice 
mentioned above. 
The fine, dusty gray ash occurs at a depth of 
15-20 cm from the surface in all profiles. It 
is most pronounced in the savannah soil and 
least so in the soil of Kipuka Ki. This layer 
looks like the leached layer of a podzolic soil. 
However, there are three arguments against this 
interpretation. First, the layer is brightest under 
savannah, which has the least acid surface layer 
(Table 1). Second, it was horizontally continu- 
ous only in Kipuka Puaulu, whereas it occurred 
in local pockets in Kipuka Ki. Third, Went- 
worth (1938), in his study of ash formations 
around Kilauea Crater, described a "gray-laven- 
der, fine sand-size ash” near the surface in sev- 
eral places which seems to fit this layer. 
The gravelly ash was described by Went- 
worth as "basalt in glass” and is well shown in 
the savannah soil, where it recurs as a thin layer 
(usually ± 5 cm thick) at depths of 30, 50, 
and 70 cm. 
Black vitreous ash appears as a layer 20 cm 
deep in all three soils, from 50—70 cm depth 
in Kipuka Ki, from 60-80 cm in the forest soil 
of Kipuka Puaulu, and from 75-95 cm in the 
savannah soil. It recurs at three places above 
this layer (at 65 cm, 45 cm, and 25 cm) in the 
savannah soil. These black layers are black not 
only from ash but also, perhaps more domi- 
nantly so, from an extremely high incorporation 
of organic carbon (between 10.1 and 15.7%, 
Table 1). 
A yellow-olive pumice layer (called "reticu- 
lite” by Wentworth) is found in the savannah 
soil incorporated into the black layer at 25 cm 
depth. Some of this pumice occurs also in both 
forest soils beneath the fine gray ash layer (Cl), 
but here it is less abundant and less well strati- 
fied (Fig. 2). 
The lower ash deposits, from the thick black 
layer (Alb) down, in both soils of Kipuka 
Puaulu are not stratified horizontally, whereas 
the upper ones are more or less horizontally 
stratified (see Fig. 2, P ± and P 2 )• Angles of 
