PHOSPHATE    DEPOSITS    IN    NOKTHERN    ARKANSAS.  469 
The  discovery  of  heavier  deposits  on  Lafferty  Creek,  about  a  mile 
southwest  of  the  above  workings,  led  to  their  abandonment  and  the 
opening  of  mines  at  the  new  place.  These  deposits  are  on  the  east 
slope  of  the  hill  that  lies  between  Lafferty  Creek  and  White  River, 
near  its  base.  The  following  section  shows  the  phosphate  beds  and 
their  geologic  relations: 
Section  containing  phosphate  beds. 
Ft.  in. 
St.  Clair  limestone. 
Brown  to  black  shale 2    0 
Low-grade  manganif erous  iron  ore 0  15 
Green  to  dark  clay  shale 0  14 
High-grade  phosphate 4J-6    0 
Manganif  erous  iron  ore 0     2 
Low-grade  phosphate 4     0 
Polk  Bayou  limestone. 
Only  the  upper  phosphate  bed  is  worked,  the  lower  being  consid- 
ered of  too  low  grade.  At  present  the  stone  is  worked  by  quarrying. 
The  main  quarry  at  the  time  of  the  writer's  visit  was  375  feet  long 
by  about  30  feet  wide.  An  additional  150  feet  at  the  north  end  was 
stripped,  ready  for  quarrying.  South  of  the  main  quarry  there  were 
two  smaller  ones,  150  and  225  feet,  respectively,  from  the  main  quarry, 
thus  making  a  total  distance  of  750  feet  along  which  the  deposit  was 
opened.  Besides  the  beds  had  been  prospected  by  sinking  shafts 
480  feet  farther  south,  at  which  point  the  dip  of  the  beds  brings  the 
deposit  below  the  creek.  The  beds  outcrop  at  points  north  of  the 
main  quarry  and  have  been  prospected  more  or  less  for  1,000  feet 
along  the  hillside.  The  total  distance,  therefore,  along  which  the 
beds  at  this  place  outcrop  and  are  known  to  be  workable  is  about 
2,200  feet. 
East  of  this  point,  on  the  opposite  side  of  the  creek,  an  adit  30  feet 
long  has  been  run  into  the  hillside.  This  adit  was  driven  apparently 
for  the  purpose  of  prospecting  the  upper  of  the  two  phosphate  beds, 
which  at  this  place  is  3  feet  4  inches  thick.  Beneath  this,  as  at  the 
main  workings,  there  is  a  phosphate  bed  of  lower  grade,  the  thickness 
of  which  could  not  be  ascertained  at  the  time  of  the  writer's  visit,  but 
it  is  probably  about  4  feet. 
As  above  stated,  it  is  only  the  upper  of  the  two  phosphate  beds 
that  is  now  quarried  for  commercial  purposes.  This  is  a  compact, 
homogeneous,  light-gray  rock  with  a  specific  gravity  of  about  3.  At 
a  distance  it  has  the  appearance  of  volcanic  tuff.  The  color  is  due  to 
small  white  particles  that  are  thoroughly  mixed  with  dark-gray  mate- 
rial. The  white  particles  appear  to  the  unaided  eye  and  under  the 
magnifier  as  if  they  might  be  small  fragments  of  bones.  The  dark- 
gray  material  is  made  up  of  particles  of  varying  size,  some  so  small 
that  they  can  be  seen  only  with  the  magnifier,  others  a  quarter  of  an 
