WARRIOR    COAL    BASIN,    ALABAMA.  213 
Pratt  seam  directly  below  is  given  in  mine  levels  and  bore  holes.  The  average  of  two 
determinations  of  the  interval  by  this  means  is  325  feet.  The  interval  between  the  Pratt 
and  Mary  Lee  seams,  473  feet,  is  obtained  from  the  lop;  of  a  bore  hole  in  Sleepy  Hollow 
near  Blossburg.  The  interval  between  the  Mary  Lee  and  Jagger  coals  is  compiled  front 
observations  made  west  of  Morris,  and  is  about  right.  The  section  between  the  Jagger  and 
Black  Creek  coals  was  measured  in  a  mine  shaft  at  Kimberly 
STRUCTURE. 
To  the  southeast  of  the  southern  field  a  great  thrust  fault  extends  from  Birmingham  to 
Mount  Pinson.  The  fault  approaches  nearesl  the  coal  measures  from  Pratt  City  to  Wylam. 
Northeastward  it  diverges  more  and  more  to  Mount  Pinson.  The  rocks  hounding  the 
fault  on  the  northwest  are  vertical  or  overturned  to  tin-  west,  with  a  southeasterly  dip. 
West  of  the  vertical  zone  the  northwesterly  dip  decreases,  so  that  in  a  distance  of  from  1 
.  to  2  miles  the  rocks  dip  only  10°  or  15°  to  the  northwest  or  are  nearly  flat.  Along  the  west- 
ern edge  of  the  field  the  rocks  dip  at  a  small  angle  to  the  southeast.  In  the  southern  field, 
as  a  whole,  the  rocks  dip,  in  general,  from  the  margin  toward  a  line  following  Black  Warrior 
River  through  Maeknally  Ford  and  extending  southwestward  to  Republic,  beyond  which 
the  rocks  are  so  nearly  horizontal  and  so  much  faulted  that  it  would  be  difficult,  with  the 
data  now  at  hand,  to  locate  the  axial  line.  The  axis  of  the  syncline  pitches  regularly  to 
the  southwest.  The  elevation  of  the  Black  Creek  coal  is  about  500  feet  above  the  sea  on 
the  axis  near  Dean  Ford  and  about  450  feet  below  sea  level  south  of  Republic,  making 
the  total  descent  of  the  seam  between  the  two  points  950  feet.  The  basin  is  therefore  spoon- 
shaped.  There  is  a  low  anticline  running  about  midway  between  the  main  synclinal  axis 
and  Coaldale  and  Kimberly,  and  a  low  syncline  near  Brookside  and  Pinkney.  The  southern 
field  is  also  much  faulted,  especially  along  the  southeastern  margin.  These  faults  are  abun- 
dant from  Wylam  to  Gift,  on  the  Northern  Alabama  Railway,  or  at  least  are  much  better 
known  in  that  area,  where  they  have  been  encountered  in  mining.  There  are  faults  also 
in  the  vicinity  of  Warrior  and  Coaldale.  A  fault  passes  just  west  of  Indio  and  another 
was  encountered  in  mining  the  Black  Creek  seam  just  east  of  Newcastle.  The  position  of 
these  faults  is  shown  on  the  sketch  map  (PI.  V).  The  course  of  nearly  all  of  the  faults  is 
N.  10°  to  20°  W.  The  displacement  varies  from  10  to  112  feet,  The  fault  planes  are 
nearly  vertical,  generally  making  an  angle  of  70°  to  80°  with  the  horizon.  The  coal  is 
reported  undisturbed  and  workable  right  up  to  the  faults.  Between  Newcastle  and  Cun- 
ningham station  is  a  disturbed  area,  the  rocks  exposed  in  the  railroad  cuts  midway  between 
the  two  places  being  greatly  distorted.  This  disturbance  is  spoken  of  as  a  fault,  but  it 
appears  to  be  an  overturned  anticline.  The  disturbed  zone  extends  northeastward  parallel 
to  Sand  Mountain  and  about  1  mile  northwest  thereof  to  Turkey  Creek,  though  the  dis- 
turbance is  not  so  great  at  all  points  along  this  course  as  it  is  between  Newcastle  and  Cun- 
ningham station. 
The  structure  of  the  northern  field  is  very  simple,  A  synclinal  axis  pitching  to  the  south- 
west appears  to  pass  through  Arkadelphia  and  cross  the  western  margin  of  the  quadrangle 
near  Locust  Fork  of  Black  Warrior  River.  The  strata  of  Arkadelphia  Mountain  dip  south- 
eastward and  those  of  the  area  north  of  Creel  dip  northeastward  to  the  axis.  The  dip  is 
low  in  both  areas,  probably  not  exceeding  100  feet  to  the  mile. 
COALS. 
GENERAL    STATEMENT. 
The  coal  seams  of  the  Warrior  basin  were  divided  by  Henry  MeCalley«  into  six  groups, 
which,  in  descending  order,  are  as  follows:  Brookwood,  Gwin,  Cobb,  Pratt,  Mary  Pee,  and 
Black  ('reek.  Each  group  consists  of  two  or  more  seams,  separated  by  from  20  to  60  feet 
of  shale  or  sandstone,  or  both,  though  sandstone  generally  predominates.  The  intervals 
between  groups  vary  from  100  to  300  feet,     The  rock  filling  these  intervals  is  usually  shale. 
aReport  on  the  Warrior  coal  basin. 
