3. APALACHICOLA RIVER BLUFFS AND BOTTOMS. 211 



ty, rises about 175 feet in a distance of a. quarter of a mile from 

 the water's edge, and Alum Bluff, in Liberty County, has a very 

 precipitous face about 160 feet high, which is perhaps the most con- 

 spicuous topographic feature in all Florida. The topography is 

 everywhere hilly, and dissected by numerous ravines and small val- 

 leys, many of which head in amphitheaters or "steep-heads" at the 

 edge of the upland. All the valleys contain streams, and most of the 

 steep-heads have one or more small springs in them. Two or three 

 of the creeks extend back from the river ten or twelve miles. The 

 Apalachicola River, which heads among the mountains of Georgia, 

 and traverses the red hills of the Piedmont region for a long dis- 

 tance, is the only stream in Florida which derives any of its water 

 from outside of the coastal plain. It is always muddy, and where 

 it is formed by the union of the Flint and Chattahoochee it fluctuates 

 at least 30 feet. Its high-water period is usually in spring, because 

 a large part of its drainage basin, unlike Florida, has wet winters and 

 dry summers. 



Vegetation Types — Next to the river are alluvial swamps (de- 

 scribed in the 3d Annual Report), with a heavy growth of deciducus 

 trees, presumably indicating a soil rich in potassium. The rich 

 slopes of bluffs and ravines are covered with short-leaf pines and 

 hardwoods, among which the magnolia and other evergreens are 

 conspicuous. A small pine woods element is found at the upper 

 or eastern edge and in the sandier soils lower down. 



On account of the broken topography and the presence of the 

 river on one side, fires are not common in this region, which is one 

 reason, perhaps the principal reason, why there is so much humus in 

 the forests. Obviously no fire can approach from the west, on ac- 

 count of the river, and the fires which sweep through the pine 

 woods on the east are not likely to travel down the bluffs very far; 

 so that there is probably no area of equal extent on the mainland 

 of northern Florida that is better protected from fire. 



Plants — The following list is based on observations made on 16 

 different days, in the following months : March, 8 ; May, i ; June, 

 4 : September, i ; December, 2. Most of the herbs were, noted in 

 the first half of March, 1909, when the writer with other members 

 of the Geological Survey camped for several days at Aspalaga. 

 That was just about the season of the year when the number of 

 flowers in rich shady woods in this latitude is at a maximum, for a 

 little later the trees leaf out and cast too dense a shade for many 

 flowers. 



