74 Transactions Tennessee Academy of Science. 



Recent Developments in theTennessee 

 PhospKate Industr}? 



By Lucius P. Brown, State Food and Drug- Inspection Bureau. 



Within the past five years a revolution has been w^rought in the 

 methods of mining Tennessee phosphate rock which is of enor- 

 mous importance to the industry at large, and particularly to that 

 -ection of it located in this State. 



I may preface my paper by saying that, as is probably known 

 to many of you, Tennessee prosphates occur in four different 

 geological horizons. From above downward these are as follows : 



First, the so-called Kidney phosphates, occurring in the Devon- 

 ian member of the Paleozoic, lying below the black shale and im- 

 mediately above the lowest member of the series. These phos- 

 phates occur as nodules of varying sizes, of fine grained texture, 

 of concentric structure, with a smooth exterior, rarely glazed, and 

 in color from gray to dark, brownish black. Occurring as they 

 do in a layer, usually limited in thickness to not over two feet, and 

 the nodules themselves lying in a matrix of barren material, from 

 which they are separated with difficulty, this horizon has given 

 rise to no important industry. The nodules are occasionally used 

 in mining the next lower layer. 



The latter, forming the so-called blue rock of Tennessee, is the 

 lowest member of the Devonian of the State. It varies in com- 

 position from an argillaceous phosphatic material through real 

 phosphate rock to an arenaceous layer containing at times only 

 traces of phospliatc. The layer appears to be co-incident with the 

 occurrence of the Devonian over a large area. It certainly ex- 

 tends all over the .State of Tennessee, and it or its representative 

 appears to occur from PcnnsyKania to ( )klalionia. ( )nlv very 

 locally is it of much value. It is now ])eing mined at onl\' one 

 ])oint, nameh'. at Ma\field .Mines, twenty miles west of Mt. IMeas- 

 ant, wliere a i)lio<])liate rocl< containing;' from ()S to 70 i)er cent 



