important processes and controls which exist in the large areas of organic sediment 
accumulation which exist in the Everglades and in the adjacent tidal plain. Some of the 
more important conclusions are as follows. Peat forms in six major types of 
environments in the area, and the peat formed can be differentiated megascopically 
with varying degrees of certainty. Only three peat types are of common occurrence. 
There are: a) Rhizophora peat, the most abundant type formed in tidal areas; b) Aquatic 
peat, in basically aquatic conditions; and c) Emergent herbaceous peat, from non-woody 
plants of the freshwater areas. Peats formed in saline grass or rush marshes may 
cover wide areas but are thin. Peats formed in bay hammock are of rare occurrence. 
The peats forming in the tidal area are higher in mineral content than those forming 
deep within the freshwater regions. This must reflect greater availability and energy 
for transport of mineral matter in the tidal area. Freshwater peats at depth in the tidal 
plain were also generally higher in mineral content than peats in the freshwater are 
indicating possible mineralization after burial. A difference was found to exist in sulfur 
content of peats in the tidal area and those occurring in freshwater conditions in the 
Everglades. The freshwater peats ranged from 0.3 to 1.0% sulfur and the saline water 
peats, with but one exception, always had more than 1.0% sulfur. This was not true, 
however, of peats of freshwater origin that presently lie within the tidal plain, so an 
increase in sulfur content possibly occurs at depth in the saline area. All peat types 
showed a gradual increase in sulfur content in the upper 1-2 ft of the section. Peats of 
freshwater origin commonly intervene between the mangrove peats of the tidal area 
and the basal calcitic mud stratum of part of that area. This is contrary to other 
theories. The sequence previously reported of mangrove peat directly over calcitic mud 
is encountered only in 7 cores. The oldest Holocene sediments known are peats that are 
approximately 5500 radiocarbon yrs in age. These reported from beneath Rodriquez 
Bank off of Key Largo. Basal peats from the northern Everglades date approximately 
5000 yrs BP. In the west coast tidal plain and beneath Florida Bay, the ages reported on 
peats are usually less than 4500 yrs with one exception that is reported here of a 
Rhizophora peat that is approximately 5000 yrs BP in age. The old peats beneath 
Rodriquez Bank have not been described sufficiently to know their environment of 
accumulation, but they occur at elevations no lower than those of the west coast that 
are apparently 500 to 1000 yrs younger. The effects of root intrusion very likely 
would make these age differences insignificant. It is suggested that the vegetational 
mosaic pattern of the Everglades is a result of a complex set of factors regulating the 
production and destruction of organic matter. For any fixed rate of supply of nutrients 
and water, it is possible for an unvariegated vegetational cover to exist if an equitable 
distribution of these materials can take place. If inequalities of distribution develop, 
then differentiation of environments will occur. In an area as large as the Everglades, 
with variations in rainfall from place to place and variations of inflow from the margins 
such differentiation seems highly likely. Also, differentiation must have occurred as 
peat began to accumulate due to variations in bedrock level. When differentiation 
results in plant communities of basically different life forms, such as the three major 
communities of the Everglades, the process of differentiation may become self- 
sustaining from variations in water losses. This may induce an essentially one-way 
transfer of nutritional substances into the areas of higher water loss. This may produce 
trends of a serial nature, but changing conditions from time to time apparently reverse 
the trend as shown by cyclic alternations of the different environments in the cores of 
this study. Fresh-appearing and probably living roots were noted in cores beneath living 
Rhizophora to depths of about 90 in. Such root intrusions may cause transport of 
oxygen to some depth and lead to decomposition of earlier formed organic matter. The 
intruded roots also have compactive effects and may make radiocarbon dates generally 
younger than the true age. Beneath other types of vegetation, root effect is much less 
apparent, but may nevertheless be important. A general rise of sea level with respect 
to the land indicated by the sedimentary record beneath the tidal plain, but locally 
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