butts.]  WARRIOR    COAL    BASIN,   ALABAMA.  365 
through  the  gap  in  Rock  Mountain  northwest  of  Tannehill,  is  about 
1,000  feet.  This  adds  350  feet  to  the  section  below  the  lowest  beds 
described  above  near  Adger.  A  number  of  good  sections  at  various 
points  show  that  the  rocks  in  this  part  of  the  general  section  are 
mostly  green  shales  Avith  beds  of  sandstone  of  varying  thickness. 
STRUCTURE  OF  THE  FIELD. 
The  rocks  of  the  Warrior  basin  within  the  Brookwood  quadrangle 
are  generally  nearly  horizontal.  They  have  a  general  southwesterly 
dip,  which  carries  rocks  that  are  over  GOO  feet  above  sea  level  in  the 
northern  part  of  the  quadrangle  to  250  feet  above  the  sea  at  Cotton- 
dale  and  less  than  150  feet  above  the  sea  at  Tuscaloosa.  In  the 
vicinity  of  Toadvine  is  the  southwestern  extremity  of  the  Blounts- 
ville  anticline,  the  axis  of  which  enters  the  quadrangle  about  1J 
miles  northwest  of  Toadvine  and  extends  to  the  vicinity  of  Scrap 
post-office.  The  axis  pitches  to  the  southwest  and  the  anticline 
seems  to  die  out,  so  that  there  is  but  slight  indication  of  its  presence 
southwest  of  Scrap.  The  axis  of  a  very  strongly  developed  anti- 
cline crosses  Valley  Creek  one-fourth  mile  above  Weaver  Mill,  ex- 
tends along  the  ridge  about  one-fourth  mile  northwest  of  Adger  and 
Johns,  passes  through  Connellsville  Junction  and  about  1  mile  south- 
east of  Yolande,  crosses  Davis  Creek  a  short  distance  south  of  the 
mouth  of  Rockcastle  Creek,  and  probably  runs  thence  southwestward 
to  the  headwaters  of  the  Middle  Fork  of  Hurricane  Creek,  along 
which  the  anticline  appears  to  die  out.  All  of  the  productive  coal 
measures  have  been  eroded  away  along  the  crest  of  this  anticline,  and 
a  small  elliptical  area  of  coal  measures  to  the  southeast  of  the  anti- 
cline has  been  cut  off  from  the  main  body  of  the  Warrior  field.  This 
area  is  known  as  the  Little  basin,  in  contradistinction  to  the  rest  of 
the  field,  which  is  spoken  of  as  the  Big  basin.  On  approaching  the 
anticline  the  rocks  of  the  Big  basin  rise  gently  at  first,  then  in  a  very 
short  distance  become  nearly  vertical,  then  flatten  and  rise  more 
gently  again  to  the  crest  of  the  anticline,  From  the  Little  basin  the 
rocks  rise  with  gradually  increasing  steepness  to  the  axis,  where  they 
become  nearly  vertical,  thus  making  an  unsymmetrical  and  nearly 
closed  fold.  From  Valley  Creek  to  Connellsville  the  zone  of  nearly 
vertical  rocks  on  the  west  begins  about  one-half  mile  from  the  axis  of 
the  anticline  and  is  1,000  feet  wide.  This  zone  continues  southwest- 
ward  from  Connellsville  and  crosses  Davis  Creek  at  the  Louisville 
and  Nashville  Railroad  bridge  east  of  Milldale.  At  this  point  the 
dip  is  60°  NW.  Between  Connellsville  and  Davis  Creek  the  distance 
of  the  zone  of  steeply  inclined  rocks  from  the  axis  of  the  anticline 
increases  to  H  miles. 
At    Adger    the    dip    of    the    rocks    from    the  crest    of    the    anti- 
