ground, thanks to a motor-vehicle track which cuts across the 
forest. In this point, and for a km. and a half approx., the re- 
lief becomes more uneven and reaches its maximum height; then, 
after a last elevation, the ground becomes flat and vegetation 
in the meantime changes, becoming now characterized, due to re- 
current Kelai river overflows, by a damp forest, which in the 
nearness of the river has been greatly exploited by the man for 
industrial purposes. 
Third phase: Land-units map definition to value the suitability 
to human inhabitability. 
From the correlation between the environmental characteri- 
»stics ascertained during the first work-phase and the measure- 
ments carried out during the second phase, it was possible to 
fix "territorial units" of the same kind, as for morphologic, 
hydrologic features and type of vegetation; these units named 
!'land-units' include the necessary information to value the 
land-suitability degree. 
As shown in the herewith attached map, five separate clas 
ses of "land-units" have been divided and marked with letters a, 
b,c,d,e. A short description of each class is given below. 
Land unit a): 
It corresponds to the lands having a slope lower than 3% 
and which extend along Segah, Siduong and Kelai rivers. These 
areas are recurrently overflowed depending on seasons and on 
their morphologic characteristics; in fact the area comprised 
between Siduong and Segah rivers presents daily overflows, which 
reach the highest frequency at least twice a month at the hi- 
ghest tides, whereas the lands near upper Siduong and Kelai are 
only exceptionally overflowed (from twice to three times in the 
year), especially in concurrence of tides and abundant rains. 
Such a situation influences existent vegetation which is 
characterized by the Swamp Forest and by typically hydro-mor- 
phism grounds. The soils represent the consequence of recent 
fluvial floods formed by elements which are heterogeneous as 
per dimensions, mineralogical compounds and lithology. 
Land-unit b): 
The topography of these grounds, characterized by lands 
with slopes comprised between 3% and 8%, represent, together 
with Land-unit c), a narrow strip between the lands subject to 
overflows and those with considerable reliefs. These lands are 
distinguishable from the next, since they can be partly over- 
flowed in case of exceptional riverfloows. The vegetation is 
mainly represented by Secondary and Swamp Forests. The soils, 
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