3IO FLORIDA GEOLOGICAL SURVEY SIXTH ANNUAL REPORT. 



i6. MIDDLE FLORIDA FLATWOODS. 



References. Gillmore (975, 1005; , Harper i (221), Harper 4 (222-224), 

 Sellards 3 (294 or 48), and U. S- soil survey of Jeffeqson County (by Jones, 

 Tlharp & Belden, 1908). Illustrated in 3d Ann. Rep., pi. 23.2. 



The above designation is applied to two disconnected areas 

 parallel to the Gulf Coast and about 20 miles from it : one in Middle 

 Florida and one in East Florida. In the Third Annual Report they 

 were not separated from what is here called the Apalachicola flat- 

 woods (region 9), but their different geographical location entitles 

 them to separate treatment, and some differences in vegetation are 

 discernible. There are about 1,000 square miles of this kind of 

 country in the area under consideration, and a few hundred ad- 

 ditional in Levy County. It has no counterpart in any other region. 

 The greater part of the portion west of the Suwannee River is 

 known as San Pedro Bay (a name which appears on few maps). 



Geology and Soils — This region is presumably underlaid by the 

 Oligocene limestones which characterize the country on both sides 

 of it, but no outcrops are known, and the limestone has little ef- 

 fect on soil or topography. There are a few spots where the vege- 

 tation seems to indicate that' there is marl within reach of the roots 

 of trees, but the prevailing soil is mostly fine sand, mixed with more 

 or less vegetable matter, well supplied with water, and probably 

 underlaid by hardpan in many places. 



In that part of the region lying in Jefferson County most of 

 the soil is mapped in the government report above cited as "Ports- 

 mouth fine sand." The following inechanical analyses of a soil, sub- 

 soil, and lower subsoil (depths not indicated) are taken from that 

 report. The soil is described as "a black fine sand with a depth of 6 

 or 8 inches," with a subsoil of "gray sand changing to reddish 

 brown at about 24 inches below the surface." The dark color of 

 the surface soil is said to be due entirely to vegetable matter; and 

 the dark material which cements the lower subsoil into "hardpan" 

 seems to be also mostly vegetable, with a small amount of iron com- 

 pounds. This soil is said to be entirely uncultivated, except on its 

 edges where it merges into the "Norfolk fine sand." 



