m 
FLORIDA GEOLOGICAL SURVEY—THIRD ANNUAL REPORT. 
has accumulated to some depth. Vegetable matter accumulates 
in this way only on such lands as are overflowed during a con¬ 
siderable part or all of the year. The largest tract of muck lands in 
the State is the Everglades. Many smaller tracts occur, however, 
throughout the State. (PI. 13, Fig. 1). 
Clay lands: The clay soils are usually of limited extent, oc¬ 
curring at places where the superficial, sands have been removed by 
surface wash. The clay soils are lacking in organic matter and 
before being farmed must be broken up and organic matter incor¬ 
porated. The accompanying illustration (PI. 14, Fig. 3), shows 
clay soils formed from the decay of impure limestones. 
The residual material here consists of a sticky clay relatively im¬ 
pervious to water and lacking in organic matter. 
Hammock lands : The term “hammock land” is most frequent¬ 
ly applied to lands underlaid by marl or limestone and supporting a 
thick growth of vegetation, including hardwood trees and cabbage 
palmetto. These lands when cleared make excellent farming lands. 
Other hammock lands occur, however, which have no evident rela¬ 
tion to marl deposits. These likewise support a heavy growth of 
hardwood trees. The soil consists of a rich humus due to the ac¬ 
cumulation of leaves. Beneath the humus is usually found several 
feet of orange yellow sand. (PI. 13, Fig. 3). 
Sandy hammock lands: The sandy hammock lands as develop¬ 
ed in the sections bordering the coasts are of wind blown sands or 
lew dunes on which vegetation has gained a foothold. Various 
hard wood trees grow on this type of land. It has been found in 
many instances desirable for orange culture. It is used also to 
some extent in vegetable growing. The open nature of the soil, 
however, results in a heavy loss of fertilizer from leeching. 
Scrub: Scrub is a term applied to very sandy lands which 
support a dense growth of shrubby plants'. The sandy pine lands 
often pass very abruptly and with no apparent reason, into scrub. 
Few attempts have been made to utilize the scrub lands for farm¬ 
ing purposes. (PI. 12, Fig. 1). 
Sand dunes :i The sand dunes both of recent and of earlier 
formation occur frequently in Florida particularly along the coast. 
The sand dune soil has been found especially adapted to the grow¬ 
ing of pineapples, the extensive pineapple farms of St. Lucie 
County being largely located on quiescent dunes. (PI. 14, Figs. 1-2) 
River swamp: The river swamp lands support a dense growth 
of hard wood trees. On the smaller streams where the elevation 
is sufficient to permit of successful drainage these lands if cleared 
would furnish desirable trucking and farming land. To clear such 
