424  CONTRIBUTIONS    TO    ECONOMIC    GEOLOGY,  1904.         [bull.  260. 
the  sandstones  that  have  been  known  as  the  "  Charleston  "  sandstone, 
which  in  this  region  contains  one  of  the  most  valuable  coals.  The 
red  shales  of  the  Conemaugh  cap  the  hills  in  the  northwest  corner, 
and  the  Manch  Chunk  red  shales  occur  in  the  valleys  in  the  south- 
east corner. 
Structure. — In  common  with  other  parts  of  the  Allegheny  plateaus, 
all  the  rocks  of  this  quadrangle  have  a  general  dip  to  the  northwest. 
This  is  not  entirely  uniform,  as  in  places  it  is  as  high  as  300  or  400 
feet  to  the  mile  and  in  some  areas  nearlv  dies  out  altogether  or  is 
reversed  in  the  case  of  a  few  irregular  anticlines  that  have  been 
found  in  the  quadrangle.  These  anticlines  are,  however,  of  only 
minor  importance,  unless  they  should  prove  to  be  areas  of  oil  and 
gas  production.  One  result  of  this  dip  is  to  divide  the  quadrangle 
into  two  coal  fields,  Gauley  River  practically  forming  the  dividing- 
line.  South  of  Gauley  River  the  rocks  belong  to  the  Sewell  and 
lower  formations,  and  in  this  respect  correspond  with  the  rocks  of 
the  New  River  coal  field.  North  of  Gauley  River  these  rocks 
are  carried  by  the  dip  below  drainage,  and  the  outcropping  rocks 
are  those  associated  with  the  Kanawha  River  coals.  The  northern 
part  of  the  quadrangle  is  therefore  an  eastward  continuation  of  the 
Kanawha  coal  field. 
New  River  coals. — Practically  all  the  present  mining  in  the  New 
River  coal  field  is  confined  to  one  or  the  other  of  two  coal  beds,  of 
which  the  lower  is  known  as  the  "  Quinnimont"  bed,  and  the  upper 
as  the  Sewell  or  Nuttall  coal  bed.  The  Quinnimont  coal  bed  is  not 
recognized  with  certainty  within  the  Nicholas  quadrangle,  its  hori- 
zon being  below  drainage  over  nearly  all  of  the  quadrangle.  Drill- 
ings just  south  of  the  southwestern  edge  report  a  good  5-foot  coal, 
which  has  been  assumed  to  be  the  Quinnimont  coal.  In  the  south- 
eastern part  of  the  quadrangle  there  are  two  or  three  coals  found 
below  the  Raleigh  sandstone,  all  of  which  in  places  reach  thick- 
nesses of  4  to  0  feet.  One  of  these  may  be  assumed  to  be  the  Quin- 
nimont coal.  The  presence  of  the  Sewell  coal  within  easy  reach 
above  drainage  has  prevented  careful  exploration  of  the  lower  seam. 
The  Beckley  coal,  lying  immediately  below  the  Raleigh  sandstone, 
may  prove  to  be  workable  over  a  considerable  extent  of  this  quad- 
rangle. It  probably  corresponds  with  one  of  the  coals  which  is  locally 
workable  in  the  southeastern  part  of  the  quadrangle,  and  which 
while  not  seen  in  the  southwestern  part  of  the  quadrangle  was  re- 
ported to  be  of  workable  thickness  in  several  places.  The  Quinni- 
mont coal  should  lie  about  180  feet  below  the  Beckley  coal  in  the 
southwestern  part  of  the  quadrangle. 
The  Sewell  coal  in  the  Sewell  formation  is  being  extensively  mined 
on  Keeney  Creek,  in  the  southwest  corner  of  the  quadrangle,  and  has 
