240 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1949 
world. This progress is credited by many people to western civiliza- 
tion, but it would have been a poor civilization indeed that could not 
have succeeded with these riches. With such abundant resources for 
its citizens, it is hard to imagine how any American government could 
possibly have failed. 
At the present time, however, people must make a go of things where 
they are, or else move into areas where a great deal of careful planning 
is necessary for successful agriculture or industry. There is no more 
Chemical Composition (%) Chemical Composition (%) 
CaO MgO oO 50 100 100 CaO MgO 
0 50 
Ol 02 Rosie _| Depth RQIYGY By 04 2.0 
O 
te NW ae 
RA XO QOS oo .0 
OS 15.4 
0.03 35.5 
—AAACDSL 
Xe oe 
O25 0: 
B. Conomingo Silt Loam 
of Maryland 
0.2 Tr 100 
a ET AP TE I TF LAD LT LD A 
7 Eee == 
FIO OKD KOO COCO O Oe, 
RK KRG ROKER KK OL 
i Nes SKS SERRE SPRERS 
‘ “ Nas OPS 
RRR SRKRKKS OKI K RK KR K 
POS Nee 
ROKK LKR KR SKLAR 
 eataces xO eatetstctes ate <q Neeetatates 
KOO 2 2, OOOOD OO 
KO sees SL RRR 
eee oat 588 “2 eeecnaeeneeneee S55 Sods % Se 
8 NNO ONO OOOO OOOO OI OOOO ONO se 
= << 
n 
a B 
{ = 
04 60 
A. Nipe Clay of Puerto Rico 
Figure 5.—A comparison of some of the chemical properties of two soils de- 
veloped from similar serpentine rocks, one in tropical Puerto Rico, and one in 
temperate Maryland. Under temperate conditions the silica has been pre- 
served, whereas it has nearly all been removed under tropical conditions. 
Further, under tropical conditions there has been an enormous increase in the 
amount of iron, and the tropical soil has been affected by weathering and soil- 
forming processes to a much greater depth. Of course, along with these obvi- 
ous chemical changes are a great many other changes reflected in the miner- 
alogical composition and physical properties of the two soils. Both of them 
are relatively unproductive naturally and require quite different methods for 
their improvement (14, 15). 
