388  CONTRIBUTIONS    TO    ECONOMIC    GEOLOGY,  1904.         [bull.  260. 
home  basin  is  flat,  and  the  coal  is  found  at  a  depth  of  600  to  800  feet 
in  the  central  part.  In  this  basin  and  westward  from  its  north  side 
to  Buck  post-office  the  coal  has  an  average  thickness  of  about  4 
feet.  From  Buck  eastward  on  the  north  side  of  the  McAlester  anti- 
cline to  the  shallow  basin  3  miles  west  of  Wilburton  the  coal  dips 
steeply  northward.  The  outcrop  has  been  traversed  and  the  coal 
prospected  in  places,  but  not  mined.  Both  the  lower  and  the  up- 
per Hartshorne  beds  are  found  to  be  of  workable  thickness  in  the 
broken  anticlinal  fold  Avest  from  McAlester.  They  average  here  4J 
and  5  feet  thick,  respectively,  and  are  of  the  usual  high  grade. 
The  coal  beds  are  faulted  down  on  the  north  side  of  the  anticline. 
In  the  vicinity  of  Wilburton,  and  also  at  Hughes,  7  miles  east  of; 
Redoak,  both  of  these  beds  are  known  to  be  of  workable  thickness. 
At  Wilburton  the  lower  is  §  feet,  while  the  upper  is  4  feet  6  inches. 
South  of  Hughes  the  lower  is  4  feet  2  inches  and  the  upper  is  4  feet. 
Farther  east,  in  the  vicinity  of  Howe,  only  the  lower  coal  has  been 
worked,  where  it  has  an  average  thickness  of  about  4  feet.  The 
upper  coal  is  present  here,  but  is  thinner  than  the  lower  bed  and 
has  not  been  mined  in  competition  with  it.  Both  the  upper  and 
lower  beds,  however,  were  mined  a  number  of  years  ago  6  miles  west 
of  Wister,  where  the  former  one  was  found  to  be  3  feet  4  inches  ancfl 
the  latter  4  feet  thick.  Both  coals  have  been  penetrated  by  shafts  and 
by  prospecting  drills  in  the  vicinity  of  Howe.  The  upper  bed  is 
shown  to  be  about  2  feet  6  inches  thick,  while  the  lower  coal  varies 
somewhat  above  and  below  4^  feet,  and  is  being  mined  and  coked.1 
Between  Wilburton  and  Howe  the  inclination  of  the  coal  varies' 
between  25°  and  35°  northward,  becoming  less  as  the  coal  is  followed 
downward. 
The  composition  of  the  Hartshorne  coal  either  changes  gradually 
westward  or  thins  out  and  another  is  found  in  nearly  the  same  posi- 
tion in  the  section,  as  shown  in  the  table  of  analyses.  These  analyses 
indicate  that  the  lower  coal  at  Howe  contains  about  19  per  cent  less 
volatile  matter  and  23  per  cent  more  fixed  carbon  than  at  Wilburton. 
From  the  south  side  of  the  field  the  Hartshorne  coal  passes  down- 
ward  beneath  Sansbois  and  Cavanal  mountains  and  then  rises  to  the. 
surface  in  several  folds  farther  north  between  these  mountains  ancji 
Arkansas  and  Canadian  rivers.  This  coal  in  the  northern  part  of 
Choctaw  Nation,  east  of  McCurtain,  is  known  locally  as  the  Panama; 
bed.  It  is  the  westward  extension  of  the  coals  mined  at  Bonanza,' 
Hartford,  and  other  places  in  the  western  part  of  the  Arkansas  field. 
The  Panama  coal  varies  somewhat  in  thickness  and  in  structure. 
Near  the  east  end  in  the  south  side  of  the  Backbone  anticline  the  coal. 
is  nearly  5  feet  thick,  but  is  divided  into  two  benches  by  several 
inches  of  shale,  while  in  the  north  side  near  the  east  end  its  thickness 
