56 GEOLOGICAL SURVEY OF ALABAMA 



Exhibit sample, serial No. 110, is from this stock and 

 representative of the Thomas mine. 



RANDOLPH COUNTY. 



Physiographically, Randolph County lies in one of the 

 most southerly sections of the Piedmont Plateau. 



Geologically, it is an eroded plateau of extensive and 

 strongly marked weathering and erosion, the underlying 

 rocks being of igneous and metamorphic origin. 



The mica bearing section of the county is mainly, if 

 not altogether, comprised within its western half, being 

 areally carried in a belt or zone of northeast to southwest 

 extension across it from the Georgia state line to Clay 

 County. 



The prevailing rocks of the micaized zone are mica and 

 hornblende schists, gneiss, and granite with their inter- 

 gradations. The general N.E.-S.W. strike of the meas- 

 ures, carries, and is subject to, frequent marked and 

 wide local variations, due to extensive folding and con- 

 tortions. 



Intrusions and interstratifications of quartz veins are 

 of general occurrence as also less frequently of horn- 

 blende, and occasionally of chlorite, schists. 



Topographically, the mica deposits developed are lo- 

 cated mainly in the hilly to mountainous section of the 

 northerly watershed or divide, at an elevation, tidal da- 

 tum, of 800 to 1200 feet, and approximately 100 to 200 

 feet above neighboring valley or stream level. So located, 

 the mica bearing pegmatites largely outcrop, resultant 

 kaolin deposits carry light over-burden of residual soil, 

 and mining operations are frequently facilitated by fav- 

 orable mine drainage, and by the more than ordinarily 

 lower level of surface water. 



As previously stated, the first attempted recovery of 

 mica commercially in Alabama, was made in Randolph 

 county near Micaville, in what was subsequently known 

 as the old Pinetucky gold mine, probably about the year 

 1870. 



Mica occurrences in that locality being more clearly 

 marked on the surface and of wider extent than at any 



