362  CONTRIBUTIONS    TO    ECONOMIC    GEOLOGY,  1904.         [bull.  260. 
mile  north  of  Milldale.  At  these  points  the  sandstone  is  rather  eoarse 
and  probably  at  least  30  feet  thick.  Below  this  sandstone  are  about 
100  feet  of  gray  shale.  In  places  this  shale  immediately  overlies  the 
Brookwood  coal,  as  shown  in  an  air  shaft  at  the  Central  mine,  which 
penetrates  60  feet  of  shale.  The  same  condition  prevails  at  Milldale. 
At  Cedarcove,  on  the  other  hand,  there  is  10  to  20  feet  of  sandstone, 
separated  from  what  is  regarded  as  the  Brookwood  coal  by  a  few  feet 
of  shale. 
Below  the  Brookwood  coal  is  about  100  feet  of  heavy  sandstone, 
which  includes  the  Milldale  and  Carter  (or  Johnson)  coal  seams. 
In  this  sandstone  is  a  band  of  conglomerate  which  in  places  is  20 
feet  thick  and  is  the  most  important  Coal  Measures  conglomerate  in 
the  quadrangle.  It  immediately  overlies  the  Milladle  coal  or  its 
horizon  over  large  areas.  The  conglomerate,  as  well  as  the  sandstone, 
is  especially  well  developed  and  exposed  along  Hurricane  Creek  and 
the  upper  part  of  Yellow  Creek.  The  sandstone  is  thick  east  of  Raz- 
burg  and  on  the  ridges  between  Davis  Creek  and  Mud  Creek.  Its 
upper  beds  pass  beneath  the  clays  and  sands  of  the  Lafayette  and 
Tuscaloosa  formations  at  Tuscaloosa,  Cottondale,  and  on  Lye  Branch 
of  Big  Sandy  Creek  about  3  miles  south  of  Coaling.  This  shows 
that  the  full  thickness  of  the  Coal  Measures  extends  for  some  distance 
south  of  the  Avell-exposed  rocks  of  the  Warrior  basin.  This  sand- 
stone is  generally  underlain  by  about  100  feet  of  stiff,  gray,  mostly 
sandy  shale,  which,  in  the  vicinity  of  Razburg,  contains  in  its  lower! 
part  many  thin  sandstone  bands,  and  between  Cohort  and  Patton 
Ferry,  as  well  as  between  Blue  Creek  and  Yellow  Creek  wTest  of  Black 
Warrior  River,  appears  to  be  partly  replaced  throughout  by  thick- 
bedded  sandstone. 
Near  the  base  of  the  shale  described  above  lies  the  Gwin  coal, 
which  is  generally  separated  by  from  5  to  20  feet  of  shale  from  the! 
next  underlying  sandstone.  This  sandstone  is  persistent  and  is  gen- 
erally  thick-bedded  or  even  massive.  In  most  places  it  is  30  to  40| 
feet  thick,  but  it  reaches  a  thickness  of  100  feet  along  the  lower  parti 
of  Davis  Creek  and  in  the  bluffs  along  the  west  side  of  the  Black 
Warrior  below  the  mouth  of  Bone  Creek.  It  underlies  the  flat  land, 
in  the  northeastern  corner  of  the  quadrangle  for  10  miles  west  from! 
Earnest.  One  and  a  half  miles  west  of  Adger  it  is  apparently  overl 
100  feet  thick. 
Below  this  sandstone  is  a  shale  whose  thickness  is  70  feet  on 
Mud  Creek,  100  feet  on  Rock  Creek,  and  apparently  220  feet  1J 
miles  west  of  Adger.  Below  this  shale  is  the  upper  Cobb  coal,j 
which  is  separated  by  20  feet  of  shale  or  sandstone  from  the  lower 
Cobb  coal.  It  was  said  that  the  shale  is  apparently  220  feet  thick 
west  of  Adger  because  the  exact  position  of  the  Cobb  coals  in  that 
