taff.]  COAL    WORK    TN    TNDTAN    TERRITORY.  395 
the  local  warping,  and  are  probably  to  some  extent  affected  by  fault- 
ing connected  with  the  Ozark  uplift.  These  structures  do  not  affect 
any  of  the  coal  beds  of  economic  value  and  do  not  require  description. 
DESCRIPTION  OF  COAL  BEDS. 
Thin  unnamed  coals. — A  coal  bed  of  locally  workable  thickness  has 
been  opened  in  the  hilly  country  12  miles  east  of  Wagoner  and  mined 
by  stripping  for  local  consumption.  It  is  not  known  to  be  thick 
enough  to  mine,  however,  except  in  the  immediate  vicinity  of  the 
workings.  It  occurs  in  local  deposits  of  shale  a  few  feet  above  lime- 
stone of  the  Morrow  formation,  the  lowest  Pennsylvanian  (upper  Car- 
boniferous) formation  in  the  western  border  of  the  Ozark  Mountain 
region.  A  thin  variable  coal  was  noted  in  the  sandstone  at  about 
the  same  position  in  the  section  near  the  mouth  of  Greenbrier  Creek, 
southeast  of  Fort  Gibson.  Some  prospects  have  been  made  on  the 
coals  south  of  Muscogee  and  in  the  vicinity  of  Wagoner.  Those 
south  of  Muscogee  are  probably  in  the  same  bed  which  occurs  in  or 
near  the  stratigraphic  position  of  the  McAlester  coal.  The  coal  lo- 
cated by  prospect  4  miles  west  of  Wagoner  is  presumably  the  same, 
while  the  thin  bed  2  miles  south  of  Wagoner  is  doubtless  lower  in 
the  rocks,  but  in  the  northward  extension  of  the  McAlester  shale. 
These  beds  so  prospected  have  shown  that  they  are  too  thin  to  be 
worked  profitably.  Four  openings  have  been  made  on  two  coal  beds 
in  the  vicinity  of  and  6  miles  west  of  Boynton.  The  crop  of  the  one 
is  within  a  mile  west  of  the  town,  and  the  prospects  upon  it  show  the 
thickness  to  range  from  8  to  18  inches.  The  other  bed,  which  occurs 
higher  in  the  rocks,  has  been  opened  near  the  southwest  corner  of 
T.  14  N.,  R.  15  E.  It  is  reported  to  crop  out  also  on  a  branch  of 
Cane  Creek  24  miles  farther  north.  The  coal  in  the  prospect  is  23 
inches  thick.  It  deserves  further  investigation,  and  may  prove  to  be 
a  valuable  deposit.  This  coal  and  the  one  near  Boynton  have  been 
mined  by  stripping  to  a  considerable  extent  for  local  use. 
Henryetta  coal. — The  next  coal  in  stratigraphic  order, -and  the  one 
that  will'  most  likely  prove  on  further  development  to  be  the  most 
valuable  in  the  northern  part  of  the  Indian  Territory  field,  is  being 
mined  at  Henryetta  and  Broken  Arrow.  It  occurs  100  to  200  feet 
beneath  the  Fort  Scott  limestone.  Mr.  G.  I.  Adams,  who  traced  the 
limestone  southward  through  northern  Cherokee  Nation,  reports  that 
a  sandstone  formation  gradually  develops  between  the  two  limestone 
members  of  the  formation  and  that  near  Arkansas  River  the  lower 
limestone  member  thins  out,  while  the  sandstone  continues  south- 
ward, gaining  in  thickness.  At  Broken  Arrow  a  heavy  sandstone 
occurs  between  the  limestone  and  the  coal.  Fast  and  south  of  Okmul- 
gee and  at  Henryetta  the  limestone  is  not  known,  but  the  sandstone 
