ly. PENINSULAR LIME-SINK REGION. 315 



The highest elevations are about 200 feet above sea-level. In the 

 most hilly portions there may be differences of elevation of 50 feet 

 in half a mile; but there seem to be no steep slopes except on the 

 immediate banks of rivers and sinks. At the other extreme the 

 country may be nearly flat. Some of the depressions contain per- 

 manent water and some are dry most of the time. There are a 

 few open sinks, caves, and natural bridges, formed by solution in the 

 usual manner. The best known natural bridge is probably that of 

 the Santa Fe River. 



Streams are decidedly scarce, and most of those which do occur 

 are rivers which rise in other regions and flow through this one 

 without receiving any tributaries except a few short spring runs. 

 Consequently swamps are likewise scarce. There are whole town- 

 ships without any running water, and many square miles without 

 any surface water at all. The rain-water sinks into the sand almost 

 immediately, and gradually finds its way into subterranean chan- 

 nels in the porous limestone. Large limestone springs are fairly 

 common, and some of them are health and pleasure resorts. 



In the more elevated areas the ground-water lies so deep that 

 it can be raised to the surface only by buckets or force-pumps. For 

 this reason, and also because of its hardness, many houses in the 

 rural districts have cisterns instead of wells. Practically all the 

 towns have artesian wells. 



Vegetation Types — At least nine-tenths of the area was orig- 

 inally covered with park-like open forests of large long-leaf pines, 

 with a "lower story" of black-jack and turkey oaks in many places. 

 The limestone outcrops are too small and often also too silicified to 

 have any perceptible effect on vegetation, except where they are 

 close to streams or sinks and thus protected from fire. There is 

 liammock vegetation along some of the streams and around some of 

 the deeper sinks, where the fires which periodically sweep the pine 

 forests can approach from only one side. Swamps are chiefly con- 

 fined to the banks of the Suwannee River, and are not very exten- 

 sive even there. The ponds are nearly all treeless, probably be- 

 cause the water-level fluctuates too much, as is the case with some 

 of the ponds in region 12. 



Plants — The following list is based on observations made on 

 22 different days, distributed through the year as follows : January, 

 4; February, 5; March, 2; April, 6; May, i; July, i; August, i; 

 December, 2. No doubt some fall-blooming plants have been over- 

 looked, but otherwise the list ought to be reasonably accurate. 

 20 



