264  CONTRIBUTIONS    TO    ECONOMIC    GEOLOGY,    1903.  [bull. 225. 
This  coal  has  an  elevation  of  about  2,000  feet  in  Log  Mountains, 
where  it  is  estimated  to  underlie  11,000  acres,  and  of  about  2,200  to 
2,300  feet  in  Mingo  Mountain,  where  its  area  is  comparatively  small. 
This  coal  is  worked  on  Mingo  Mountain  and  on  Stony  Fork  and  Coal 
Creek  in  Log  Mountains. 
Sandstone  Parting  coal.— From  160  to  250  feet  below  the  Poplar 
Lick  coal,  the  interval  increasing  from  north  to  south,  is  a  coal  that 
shows  in  most  sections  a  hard  sandstone  parting.  It  is  not  certain 
that  the  sandstone  parting  occupies  the  same  stratigraphic  position  in 
the  coal  at  different  points,  as  sometimes  it  comes  near  the  top,  some- 
times near  the  bottom.  It  has  been  much  used  by  engineers  in  the 
field  as  a  key  coal,  especially  in  tracing  the  Poplar  Lick  coal.  It  is 
mined  commercially  at  the  Yellow  Creek,  Nicholson,  and  Ralston  No. 
2  mines  on  Mingo  Mountain.     Two  sections  are  given: 
Section  of  Sandstone  Parting  coal  in  Log  Mountains. 
Ft.     In. 
Coal 2  2 
Sandstone ~ 0  2 
Shale 0  2£ 
Coal 0  6 
Total ------ 3       h 
Section  of  Sandstone  Parting  coal,  Mingo  Mountain. 
Ft.  In. 
Coal 0  3 
Clay,  none  to 1  0 
Coal. 0  3J 
Clay 1 0  1 
Coal 2  10 
Sandstone 0  3 
Coal 1  2 
Total 5     lOj 
This  coal  is  hard  and  the  sandstone  tends  to  stick  to  the  coal.  It 
would  hardly  be  classed  as  workable  in  Log  Mountains. 
Mingo  coal. — This  is  the  most  important  coal  in  the  Bennett  Fork 
region  and  to  the  west.  It  is  not  workable  on  Stony  Fork  or  to  the 
north.  On  Bennett  Fork  it  lies  about  250  feet  below  the  last-named 
coal,  five  or  more  coals  occurring  in  the  interval.  Its  position  can 
readily  be  determined,  as  it  comes  about  40  feet  above  the  upper  of 
two  sandstones  that  make  almost  continuous  cliffs  through  this  area. 
The  uppermost  of  these  cliffs,  which  is  the  more  prominent,  was  used 
as  a  key  rock  in  this  part  of  the  field  and  followed  around  the  moun- 
tain to  connect  the  coal  of  the  different  valleys.  The  Mingo  coal  is 
about  1,500  to  1,600  feet  above  sea  level  in  the  valley  of  Stony  Fork 
and  1,700  to  1,800  feet  along  the  upper  part  of  Bennett  Fork.  It  has 
a  regular  parting  of  6  to  8  inches,  which  toward  the  lower  and  upper 
