PRELIMINARY REPORT ON PEAT. 243
in Florida, mostly in the dry season, without noticing any variation in its color; and as in its lower courses it has cut a channel through limestone, it may without serious error be regarded as a case of swamp water on calcareous rock.
The estuarine swamps and marshes at the mouth of this river are quite interesting, and in some respects unique. A mile or two from the coast the river divides, enclosing between its arms an island a few thousand acres in extent, known as Hog Island. The coastward edge of this island is marsh, similar in general appearance to the salt marshes elsewhere along the Gulf hammock coast, but with hardly a trace of salt water vegetation. The explanation of this rather anomalous occurrence of fresh water vegetation immediately on the borders of the Gulf of Mexico, without the protection of any sort of barrier beach, is probably to be found in the extreme shallowness of the water. According to the U. S. Coast Survey charts, there are places in the immediate vicinity where the Gulf has a depth of only a foot or two, and several miles out where it is only five feet deep. Under these conditions the fresh water which is continually pouring out of the two mouths of the river must make the salt water very dilute for some distance in every direction.
Going up either mouth of the river, small trees, of every kind mentioned in the following list except perhaps the last two, soon begin to appear in the marshes, gradually become larger and denser until in the inland half of the island they form a compact forest. There is practically no dry land on the island, the soil being all peat or muck, so that it is not a very easy place to explore. On April 15, 191o, I went around it in a launch, penetrated into the interior on foot a short distance in two or three places, and identified the following plants:
TREES
Sabal Palmetto (cabbage palmetto) Nyssa biflora (black gum.)
Taxodium distichum (cypress) Acer rubrum (maple)
Magnolia glauca (bay) funiperus Virginiana (cedar)
Fraxinus profunda? (ash) Persea pubescens (red bay)
SHRUBS AND WOODY VINES
Myrica cerif era (myrtle) Cornus stricta?
Rhus radiccans (poison ivy) Part henocissus quinquefolia (VirPhoicadendron flaz'escens (mistle- ginia creeper)
toe) Baccharis halimifolia
Itea Virginica Aster Carolinianus