SOILS. 141 
is especially rich. During the rainy season it is for the most part 
flooded, but in December it becomes sufliciently dry to admit of cul- 
tivation, and yields a harvest of corn at a time when corn can not be 
grown on higher and drier land. In the northern part of the island 
the regions known as Santa Rosa, Matiguag, and Yigo are famous 
for the excellence of their products. These regions have been less 
cultivated than those in thé center and south of the island, owing to 
the fact that there are no sources of water supply for man or animals 
with the exception of one or two small streams in the immediate 
vicinity of Mataguag and Santa Rosa, where the platform of porous 
coralliferous limestone is pierced by volcanic outcrops. An analysis 
of the best soils of this part of the island shows that they consist 
largely of heavy reddish clay, and are comparatively rich in nitrates. 
Where the land is uncultivated it is covered with forest growth. 
When the forest is cleared (Pl. XXIII) it is first planted in land taro, 
bananas, and plantains, and when the stumps are burned and the land 
sufficiently clean coconuts, cacao, and coffee are planted. Oranges of 
excellent quality are produced in the Yigo and Santa Rosa districts, 
and in sheltered places fine cacao is successfully grown. The coffee 
of these districts is also of excellent quality. The determination of 
the water soluble plant. food constituents in these soils, which was 
made by the Bureau of Soils, United States Department of Agricul- 
ture, shows that they compare very favorably with tropical soils in 
general. All are relatively high in lime, due to their coral origin. 
The amounts of potassium in the samples examined are large as com- 
pared with the soils of the United States, and the large amount of 
nitrates in the Yigo and Matdguag soils is especially noteworthy, 
characterizing them as very productive. 
Tur mEsA.—The northern half of the island consists almost entirely 
of a raised platform of coralliferous limestone called the ‘*mesa” or 
‘meseta.” Its surface is covered with a layer of soil often only a few 
inches in depth, of a reddish color from the presence of oxide of iron 
in the decomposing coral of which it largely consists. Beneath the 
superficial layer the subsoil is of rotten coral, and beneath this is a solid 
mass of the hard coral composing the ancient reef, cemented together 
by carbonate of lime formed by the action of water upon the oxidized 
surface limestone. Where the meseta has been cultivated for a long 
time its productive power is small, and the natives declare it to be 
‘Scansada,” or tired. Much of the mesa produces excellent tobacco, 
sweet potatoes, and maize, though no effort is apparently made to fer- 
tilize it artificially. Abandoned tracts on the mesa soon become over- 
grown with scrubby bushes, including cassia, indigo, sappan wood, 
and other leguminous plants. The natives understand the economy of 
allowing them to lie fallow for a period of time sufficient for the 
undergrowth to forma thicket, and in selecting a tract for planting 
