KAOLINS    AND    FIRE    CLAYS    OF    CENTRAL    GEORGIA.  311 
Lime Trace. 
Magnesia Trace. 
Sodium  oxide 60 
Potassium  oxide '. 26 
Titanium  dioxide 1 .  37 
Sulphur 04 
Phosphorus  pentoxide Trace. 
100. 60 
The  kaolin  contains — 
Sand 8.  609 
Ferric  oxide 035      • 
Clay  substance 91.  356 
100. 000 
The  following  geological  section  was  made  along  a  sloping  ridge  at 
the  point  where  this  kaolin  outcrops: 
Section  along  ridge  3  miles  east  of  Gibson,  Ga. 
Feet. 
1.  Red,  cross-bedded  sand  capping  the  ridge 30 
2.  Drab  and  green  colored  soft  calcareous  clay;  contain    Eocene 
fossils 20 
3.  Thin-bedded,  soft,  fossiliferous  limestone 5 
4.  Calcareous  clay  and  sand 5 
5.  Kaolinic  quartz  sand;  contains  large  pellets  of  white  clay  and 
disseminated  kaolin;  belongs  to  the  Tuscaloosa  formation. ....   15 
6.  Kaolin,  stained  with  iron  oxide  near  the  top 6-f 
Two  miles  east  of  Gibson  there  is  a  bed  of  flint  fire  clay  20  feet  in 
thickness.  This  is  a  cream-colored  clay,  with  yellow  iron  stains,  con- 
taining 18  per  cent  of  quartz  sand  and  only  1.42  per  cent  of  fluxing 
impurities.  It  is  the  hardest  clay  found  in  central  Georgia,  having 
a  hardness  of  2.5  to  3.  It  breaks  with  a  conchoidal  and  splintery 
fracture  and  disintegrates  very  slowly  on  exposure  to  the  weather. 
No  plasticity  is  developed  even  by  fine  grinding.  It  is  very  refrac- 
tory and  with  a  plastic  clay  for  a  bond  will  make  excellent  fire  brick. 
HEPHZIBAH. 
The  Albion  Kaolin  Company  is  mining  kaolin  at  Hephzibah.  The 
kaolin  here  is  12  feet  thick,  soft,  free  from  grit,  and  plastic.  It  is  in 
one  massive  jointed  bed,  overlain  by  about  20  feet  of  indurated  and 
nonindurated  sand  and  gravel,  which  gradually  increases  in  thickness 
away  from  the  bed.  The  kaolin,  on  account  of  its  freedom  from  grit 
and  its  softness,  is  an  excellent  paper  clay,  and  the  product  of  the 
mine  is  shipped  to  northern  paper  mills.  The  clay,  however,  is  also 
adapted  to  the  manufacture  of  pottery.  The  following  analysis  of 
the  crude  clay  represents  its  average  quality. 
