PRELIMINARY REPORT ON PEAT. 251
HERBS
Tillandsia usneoides (Spanish Osmunda regalis (a fern)
moss) Vallisneria spiralis (eel-grass) (unSaururus cernuus der water)
Lorinseria areolata (a fern) Piaropus crassipes (water hyaRhynchospora corniculata cinth) (introduced)
Centella repanda
About a mile south of Palatka the peat is about 20 feet deep at the water's edge, and of course of very good quality, because the St. Johns River is never muddy. (See analysis under locality No. 8.) In such an accessible locality it ought to be valuable.
About a mile north of Palatka the river is bordered in part by saw-grass marshes, and a plant for the manufacture of fertilizer filler from peat has recently been erected there. Similar marshes probably occur at many other places below Palatka, but I have not had opportunity to examine any of them. There are extensive peat deposits on two tributaries of the lower St. Johns, namely, Julington Creek and Crescent Lake, which might also be classed as estuarine, but they are so unique and interesting in some ways that discussion of them will be deferred to a subsequent chapter.
NOIN-CALCAREOUS SEEPING SWAMPS.
Wherever the bottom of a valley dips slightly below the general ground-water level the water slowly oozes out and flows away, and certain plants which prefer a perpetually saturated soil establish themselves. In Florida such places are practically immune from the fires which periodically sweep through the pine forests, and a comparatively dense growth of trees and shrubs is the result. The decaying wood and leaves from these keeps forming peat, the thickness of which is limited only by the nature of the surrounding topography and the height to which the ground-water level can be raised by capillary attraction. In the final stage of such a swamp the upper layers of peat would be dry enough for the process of humification to set in, and the vegetation would approach the hammock type. It is quite likely that many of our low hammocks have had just such a history.
The seeping swamps of Florida are of many different types. The commonest are those of branches and small creeks, which are frequent in nearly all parts of the state, but need not be described here, as they are too shallow to be considered as sources of peat. A few of the other types, with deeper peat, will now be described separately.