390 
CONTKIBUTIONS    TO    ECONOMIC    GEOLOGY,  1904. 
[BULL.  260. 
between  McCurtain  and  Sansbois,  north  of  Sansbois,  and  north  of 
Starvilla.  In  this  region  north  of  Sansbois  Mountain  the  coal  bed 
varies  in  thickness  from  1  foot  6  inches  to  2  feet  2  inches,  and  all 
information  obtainable  goes  to  show  that  it  is  clear  of  shaly  impuri- 
ties and  of  high  grade. 
The  quality  of  the  McAlester  coal  in  the  southern  part  of  the  field 
east  of  the  Missouri,  Kansas  and  Texas  Railroad  is  uniformly  high. 
It  is  slightly  harder  than  the  Hartshorne  coal,  having  an  advantage 
both  in  mining  and  in  shipping  qualities.  In  the  Lehigh  basin  the 
coal  contains  a  higher  percentage  of  sulphur  and  ash  and  is  weaker 
structurally  than  the  coal  in  the  McAlester  district  farther  east. 
While  the  coal  is  thinner  north  than  it  is  south  of  Sansbois  Mountain, 
it  is  of  superior  quality,  running  lower  both  in  ash  and  in  sulphur 
than  in  other  parts  of  the  field,  so  far  as  known.  The  following  is  a 
record  of  analyses  of  the  McAlester  coal : 
Proximate  analyses  of  Lehigh,  McAlester,  and  Stigler  coals. 
Location. 
Mois- 
ture. 
Volatile 
combus- 
tible mat- 
ter. 
Fixed 
carbon. 
Ash. 
Sul- 
phur. 
Phos- 
phorus. 
Lehigh,  Choctaw  Nation 
1  mile  west  of  McAlester,  Choc- 
taw Nation  . 
•  3.  56 
2.08 
1.74 
1.06 
1.25 
41.61 
37. 52 
37.00 
23.  01 
22.49 
41.12 
56.02 
56.86 
72.47 
62. 18 
13.  71 
4.38 
4.40 
1.92 
7.88 
4.  56 
.80 
.65 
.91 
6.88 
0.024 
.016 
Krebs,  Choctaw  Nation 
2  miles  west  of  Stigler,  Choctaw 
Nation . . 
H  miles  northwest  of  Starvilla, 
Cherokee  Nation 
.014 
The  McAlester  coal,  as  well  as  the  Hartshorne,  is  coked  successfully 
for  commercial  use,  making  a  coke  of  good  grade.  One  hundred  and 
eighty  ovens  are  in  operation  at  Krebs  and  Alderson. 
Cavanal  coal. — This  coal  bed  is  situated  in  the  Savanna  formation 
immediately  beneath  the  middle  group  of  sandstone  beds,  and  occurs] 
in  workable  thickness  around  the  east  and  south  sides  of  Cavanal] 
Mountain  from  the  town  of  Poteau  to  a  point  5  miles  west  of  Wisteij 
The  dip  of  the  coal  at  the  outcrop  is  variable  between  C>°  and  10°, 
The  outcrop  was  traced  around  Cavanal  Mountain  and  the  thickness 
of  the  coal  was  found  to  vary  slightly  from  place  to  place  wherj 
mining  and  prospecting  had  been  carried  on.  Between  the  limits 
where  the  coal  is  known  to  be  workable  it  varies  from  2  to  ?>  feet. 
But  little  is  known  of  this  coal  in  the1  western  part  of  Cavanal  Moun- 
tain or  elsewhere  farther  west.  Coals  have  been  found  in  the 
Savanna  formation  near  South  McAlester  and  in  the  south  side  of 
