GEOLOGY OF FLORIDA 289 



64 .88 inches {Climatological Report, 191 2). The maximum for any 

 one station during this exceptional year was 91 .61 inches, at Mo- 

 Hno in Escambia County. The maximum recorded rainfall for any 

 one month at a single station is 31 . 26 inches, which is credited to 

 August, although in July, 1916, the rainfall at Bonifay, in Holmes 

 County, was 30 . 6 inches. The rainfall of a single storm lasting 

 somewhat more than one day has been known to exceed 10 inches. 

 The rainfall for a period of twenty-four hours is known to have been 

 as much at a single station as 13.18 inches. As much as 3.90 

 inches is recorded as having fallen in one hour at Tampa in August 

 {Climatological Data, sec. 84). 



DEAINAGE 



The drainage conditions in Florida are in some respects excep- 

 tional. In that part of the state in which limestones are near the 

 surface, especially on the upland limestone section of the interior, 

 the drainage is largely subterranean, although much of the water 

 that thus enters the earth reappears through large springs which 

 supply streams. In the limestone belt the rainfall enters the earth 

 either directly through the surface materials or through disappearing 

 streams which discharge their flow into porous rocks. The sub- 

 terranean drainage is best developed in that part of the state known 

 as the "lime sink" region, where aside from the main rivers there 

 are few or no surface streams. Partial subterranean drainage, 

 however, is characteristic of a very much larger area, and for the 

 state as a whole the average for surface run-off is low. 



The prevailingly level country over much of the state, together 

 with porous soils, results in but limited surface wash. However, 

 in the more hilly parts of the state the wash of road beds and soils 

 under the influence of heavy rains is sometimes serious. 



The streams of Florida for the most part have a slight gradient 

 and are slow-moving. The drainage of the westward extension of 

 the state is through numerous streams, of which the Apalachicola is 

 the largest, having a general north-south direction. The drainage 

 basins of the peninsula are for the most part ill-defined. The St. 

 Johns River, which flows north, and the Kissimmee River, which 

 flows south, receive much of the drainage of the Atlantic slope. 



