WATSON AND GOOCH: VIVIANITE FROM FLORIDA 83 



recent letter to one of us (Watson), Dr. E. H. Sellards, State 

 Geologist of Florida, states that a specimen of vivianite was 

 brought to his office in August, 1916, by a citizen of Avon Park, 

 Desoto County, Florida. The exact locality was not given, 

 but Dr. Sellards says the mineral presumably came from south 

 of Avon Park, which would place the locality some distance to 

 the southeast of the land pebble phosphate area as defined on 

 the map by Matson.- The vivianite was associated with bog 

 iron ore. 



Vivianite is apparently a rare mineral in the Florida phos- 

 phate deposits, and so far as we are aware it has not hitherto 

 been described, although noted in places in association with 

 phosphate deposits of the Florida type. Because of these facts 

 and the general character of the vivianite crystals found near 

 Plant City, the occurrence is regarded of sufficient interest and 

 importance to warrant a published record. 



GEOLOGIC SECTION 



The vivianite occurs in a ferruginous or dark-yellow ocherous 

 matrix of earthy character about 20 feet below the surface at 

 the contact of the pebble phosphate bed with the "bedrock" 

 (clay in this section), and partly in each. The vivianite matrix 

 covers an area of approximately 1000 square feet, with the viv- 

 ianite-bearing portion limited to about 20 feet square and 2 or 

 3 feet deep. 



The section follows. 



Overburden: Thickness in feet 



Black sandy soil containing organic matter 2 



Sand with very little admixed clay, partly 



indurated and colored red by iron oxide 12 



Clay, more or less phosphatic 1 



Phosphate : 



Pebble phosphate with some sand 4-6 



Bedrock: 



Dark yellow ocherous earth, locally hardened 

 and red in color, containing besides vivianite 

 scattered pebbles of phosphate and small 

 rounded quartz grains 2+ 



2 Matson, G. C. Op. cit. Folded map in pocket. 



