bcttr.]  WARRIOB   COAL   BASIN,   ALABAMA.  363 
section  is  not  known  to  the  writer.  The  position  of  a  coal  that  is 
supposed  to  be  the  Pratt  coal  is  known,  however,  and  assuming 
that  the  interval  between  the  upper  Cobb  and  the  Pratt  coals  is 
approximately  the  same  in  the  section  west  of  Adger  as  in  a  diamond- 
drill  hole  on  Black  Branch  in  the  vicinity  of  Virginia  mine,  the  in- 
terval between  the  Cobb  upper  coal  and  the  base  of  the  sandstone  at 
the  top  of  the  shale  would  be  220  feet.  ^  This  part  of  the  section  west 
of  Adger  does  not  show  all  the  rocks  and  it  is  not  known  that  it  is 
fully  occupied  by  shale,  but  shale  is  the  only  rock  seen  and  is  assumed 
to  persist  throughout.  From  the  thicknesses  given  above  it  appears 
that  the  interval  between  the  Gwin  coal  and  the  upper  Cobb  coals 
varies  from  120  to  350  feet,  according  to  locality. 
Below  the  Cobb  coals  is  a  rather  coarse,  thick-bedded  sandstone, 
which  appears  to  be  persistent  throughout  the  quadrangle.  It  is 
especially  prominent  along  Valley  Creek  for  several  miles  below  the 
mouth  of  Black  Branch,  and  in  places  makes  a  long  bluff  30  to  50 
feet  high.  Its  thickness  varies  from  20  to  60  feet,  40  feet  being  per- 
haps a  fair  average.  In  the  vicinity  of  Toadvine  this  sandstone  is 
succeeded  below  by  a  stiff  sandy  shale  about  170  feet  thick,  but  along 
Valley  Creek,  from  Lick  Creek  to  Blue  Creek  and  west  of  Adger,  the 
equivalent  rocks  appear  to  reach  a  thickness  of  300  feet  and  to  con- 
sist of  shaly  to  laminated  sandstone  rather  than  shale. 
At  the  base  of  the  shale  just  described  lies  the  Pratt  coal.  The 
interval  between,  the  Pratt  coal  and  the  Cobb  coals  varies  with  the 
thickness  of  the  intervening  shale  and  sandstone  from  200  feet  at 
Toadvine  to  365  feet  on  Black  Branch  and  at  Adger.  The  Pratt 
coal  is  underlain  by  about  15  to  20  feet  of  shale  or  shale  and  sand- 
stone, and  just  below  these  beds  lies  the  Nickel  Plate  coal.  This  is 
succeeded  by  from  60  to  100  feet  of  shale  and  heavy  sandstone, 
beneath  which  lies  the  American  coal.  Then  follows  180  feet  of 
sandstone  containing  shale  bands  and  two  small  seams  of  coal.  The 
upper  beds  of  the  sandstone  are  well  displayed  along  Valley  Creek 
from  Toadvine  to  the  Narrows,  and  along  the  southeastern  margin  of 
the  Big  basin,  to  be  described  later,  it  is  especially  conspicuous  by  its 
nearly  vertical  attitude  along  a  line  of  outcrop  which  crosses  Valley 
Creek  at  the  mouth  of  Blue  Creek,  passes  about  H  miles  west  of 
Adger,  just  west  of  the  old  Connellsville  mine,  and  probably  crosses 
Davis  Creek  some  distance  above  the  Louisville  and  Nashville  Hail- 
road  bridge.  This  sandstone  affords  a  good  means  of  locating  and 
identifying  the  Pratt  coals.  Immediately  below  it  is  about  300  feet 
of  shale,  at  the  base  of  which  lies  the  Mary  Lee  coal.  Computed 
measurement  in  the  vicinity  of  Short  Creek  gave  about  625  feet  for 
the  interval  between  the  Pratt  and  Mary  Lee  seams.  A  similar 
measurement  west  of  Adger  gave  650  feet,  while  the  interval  meas- 
