60 FLORIDA GEOLOGICAL SURVEY—FOURTH ANNUAL REPORT. 
the light sands, as this is determined by texture and thickness of 
the sand. Sand dunes and other accumulations of sand may be 
relatively steep and yet not wash. The soil types in the Norfolk 
series described in Florida are Norfolk sand, coarse sand, fine sand, 
loam, sandy loam, fine sandy loam, and very fine sandy loam. The 
Norfolk is by far the most extensive series in Florida. Of the total 
area mapped in detail by the Bureau of Soils, about 65% is referred 
to the Norfolk series. In the state as a whole probably not less than 
75% of the soils will in this system be classed in the Norfolk series. 
ORANGEBURG SERIES. 
The Orangeburg series differs from the Norfolk series in having 
a red sandy clay sub-soil instead of a yellow or blotched subsoil. 
The top soil of the Orangeburg series may be light colored, although 
it is usually red, due to admixture of material from the red clay sub¬ 
soil. The Orangeburg soils, as a rule occupy the slopes, while the 
Norfolk soils usually rest upon more level ground. The Norfolk soils 
are subjected to little or no surface wash and the constant seepage 
of surface waters removes most of the clay particles, leaving the 
light colored sandy soils. The Orangeburg soils lying upon the 
slopes are subjected to more rapid change than the soils on level 
ground, and the renewal of new soil material from the sub-soil is 
proportionately more rapid. The soils moreover, are not so long 
exposed to the leaching processes that remove the soluble constitu 
ents. For this reason the soils on hillside slopes, if prevented as 
they easily are from destructive surface wash, are, other conditions 
being the same, more enduring than those on the level lands. 
The types of Orangeburg soils that have been recognized in Flor¬ 
ida are the following: Orangeburg sand, coarse sand, fine sand, 
loam, sandy loam, coarse sandy loam, and fine sandy loam. The 
areas, of chief distribution of the Orangeburg soils are the red clay 
hills of northern, western and central Florida. 
PORTSMOUTH SERIES. 
The soils of the Portsmouth series contain more or less organic 
matter which give them a dark color. The sub-soil may be gray, yel¬ 
low, or mottled yellow and gray. Mottled sandy clays form the 
sub-soil of the loams of this series. For agricultural purposes the 
Portsmouth soils, as a rule, require drainage. 
The differences between the soils of the Norfolk and the Ports¬ 
mouth series are due primarily to differences in the drainage condi¬ 
tions from which arise other differences in the chemical and physi- 
