58 FLORIDA GEOLOGICAL SURVEY—FOURTH ANNUAL REPORT. 
can accumulate to form soils, and on less steep slopes the soil is ma¬ 
terially affected by the removal of the finer ingredients. Even on 
level surfaces, under certain conditions of sub-drainage, the finer 
materials of the soil are segregated from the coarser. 
OTHER TERMS DESCRIPTIVE OF SOILS. 
A classification of soils in common use is that which refers to 
the soil ingredients rather than to the manner of formation. The 
clay soils are those in which clay predominates. Sandy soils are 
those in which sand is an abundant mineral constituent. Silty soils 
consist of finer material, including fine sand and finely divided clay. 
Loams are those soils having an admixture of sand and clay. Other 
terms as calcareous, ferrugineous and muck soils are self-explanatory. 
The clay soils are often referred to as heavy, and the sandy soils and 
loams as light, referring to the ease with which they may be culti¬ 
vated. The heavy soils, although more difficult to farm, are fre¬ 
quently very durable owing to their clay ingredients, the decompo¬ 
sition of the clay minerals supplying plant food. 
As has been previously stated, the presence of water in soils 
retards oxidation and preserves a high constituent of organic mat¬ 
ter. Under favorable conditions a considerable thickness of vegeta¬ 
ble matter more or less decayed accumulates from the growth of 
vegetation, forming muck deposits. The muck, therefore, accumu¬ 
lates wherever the vegetation is dense and there is sufficient water 
covering the surface to prevent the oxidation of the vegetable matter. 
The muck deposits of Florida are extensive. Peat is likewise essen¬ 
tially an accumulation of vegetable matter which has been preserved 
from decay by being immersed in water containing organic acids. 
It is customary to apply the term “muck” to vegetable material that 
is available, after being drained, for agricultural purposes. Peat is 
reserved for thicker accumulations of vegetable material which, 
being largely immersed under water, are not in a rotted condition, 
or at least not more than a surface coating is so rotted. Muck is 
also applied to vegetable material that may be high in clay or other 
impurities. 
SOIL NAMES IN USE BY THE BUREAU OF SOILS OF THE THE UNITED 
STATES DEPARTMENT OF AGRICULTURE. 
For convenience of description and reference specific names are 
applied to soils. The most extensive system of soil nomenclature 
now in use is that established and followed by the Bureau of Soils 
