230 FLORIDA GEOLOGICAL SURVEY SIXTH ANNUAL REPORT. 



formation, or both conditions may occur. Where the red loam ap- 

 proaches the surface small ferruginous concretions are common, as 

 already noted in the lime-sink region. 



A brick-red loam, commonly referred to the Lafayette forma- 

 tion, and more characteristic of localities farther inland, where the 

 summers are a little drier, is- common at and near the surface in the 

 northern part of Escambia County, and perhaps elsewhere. Around 

 the head-waters of Alaqua Creek in Walton County there is a few 

 square miles of reddish clayey soil muCh like that in the Knox Hill 

 country, and with similar vegetation, but apparently completely iso- 

 lated, and too small to be treated separately. Running east and west 

 througli the middle of Walton County is a broad sandy ridge (fol- 

 lowed by the L. & N. R. R.) whose origin has not been explained. 

 On this ridge, as in deep dry sand in other parts of the region, sala- 

 manders are abundant and gophers common. 



The following chemical analysis from Dr. Eugene A. Smith's 

 report on Florida in the 6th volume of the Tenth Census (page 199) 

 represents nine inches of soil near Mt. Pleasant, Gadsden County, 

 where the vegetation was long-leaf pine, narrow-leaf black-jack 

 {Qncrcus cincrea), round-leaf black-jack {Qucrcns Marylandka), 

 red oak {Qucrcns falcata), post oak, hickory, oak runners {Qucr- 

 cns pnmila?), huckleberries, wire-grass, devil's shoestring, {Cracca 

 Virginiana), wild oats {Sorghastrum secundum?) , vanilla ( Trilisa 

 odoratissima?) , etc. 



Water and organic matter 2.422% 



Potash -045% 



Soda -018% 



Lime -064% 



Magnesia -OOS^o 



Brown oxide of manganese .220% 



Phosphoric acid -— .066% 



Sulphuric acid .091% 



Peroxide of iron -941% 



Ahimina 1-339% 



Sohible siHca ^ -• 1.721% 



InsoUible matter 93-362% 



As compared with other northern Florida soils analyzed in the 

 sp.me report, this has the lowest percentages of potash, magnesia 

 and phosphoric acid, next to the lowest of lime, and the highest of 

 manganese and sulphur. (Little is known about the relations of the 

 two last-named constituents to vegetation.) 



Mechanical analyses of several typical upland soils of the same 



