CLEARFIELD   COAL   FIELD,  PENNSYLVANIA. 
By  George  H.  Ashley. 
Introduction. — Clearfield  coal,  from  Clearfield  County,  Pa.,  has  long  been  one  of  the 
itandard  coals  for  comparison  all  through  the  Appalachian  region.  It  is  regularly  quoted 
In  the  eastern  markets,  and  with  70  per  cent  or  over  of  fixed  carbon,  22  per  cent  of  volatile 
hatter,  and  8  per  cent  of  waste,  it  is  typical  of  the  highest  grade  of  bituminous  coal,  espe- 
lially  of  the  so-called  "semibituminous  "  class.  To-day  interest  in  this  coal  field  centers  in 
Is  present  condition  and  the  possibilities  of  its  extension  in  different  directions.  This 
aper  is  based  on  recent  field  work  on  the  Houtzdale,  Curwensville,  and  Punxsutawney 
iuadrangles,  which  cover  nearly  all  of  the  southern  half  of  Clearfield  County,  and  include 
(he  famous  Moshannon  coal  basin,  from  which  all  of  the  original  Clearfield  coal  was  derived. 
See  fig.  11.) 
;  Structure. — This  area  is  divided  into  two  basins  by  a  broad  arch  which  enters  the  county 
rom  the  south  between  Coalport  and  Westover,  then  passes  northeastward  near  McCartney, 
>etween  Belsena  Mills  and  Boardman,  to  a  point  between  Wallaceton  and  Bigler.  This  arch, 
vhich  rises  and  is  very  broad  toward  the  northeast,  lifts  the  rocks  until  practically  all  the 
workable  coals  have  been  removed  northeast  of  Belsena  Mills.  To  the  southeast  of  this 
rch  lies  the  old  " first  basin"  of  the  First  Pennsylvania  Survey,  in  which  occurs  the  Moshan- 
lon  coal,  while  to  the  northwest  lies  the  "second  basin."  The  coals  of  this  district  belong 
nainly  in  the  Lower  Productive  Measures,  or  Allegheny  formation,  including  the  beds  from 
he  Brookville  or  Clarion  coal  up  to  the  Upper  Freeport  coal.  The  presence  of  ten  to  twelve 
oals,  as  against  seven  at  the  type  locality,  the  known  splitting  of  both  the  "D"  and  the 
B"  beds,  and  the  limited  data  over  many  areas  have  led  to  a  continuation  of  the  use  of 
;he  letters  as  used  in  this  field  by  the  mining  men,  running  from  "A"  for  the  Brookville  coal 
o  "E"  for  the  Upper  Freeport  coal.  By  the  use  of  these  letters  it  is  intended  to  suggest 
relative  position  and  approximate  correlation,  without  implying  exact  correlation.  The 
principal  coals  to  which  they  are  applied  lie  from  40  to  60  feet  apart  through  a  vertical 
space  of  250  feet.  Of  these  the  most  important  coal  has  the  relative  position  of  the  Lower 
Freeport  coal,  or  coal  "D,"  on  Allegheny  River. 
Moshannon  basin. — The  two  basins  may  be  again  subdivided  for  purposes  of  detailed 
discussion  into  a  number  of  subbasins,  to  be  treated  in  order  from  northeast  to  southwest. 
Of  these  the  first  is  the  Houtzdale-Osceola,  or  old  Moshannon  basin,  including  the  coal 
lying  in  the  Moshannon  Creek  and  Beaver  Run  drainage.  This  basin  lies  along  and  just 
within  the  southeastern  edge  of  the  county,  from  a  point  a  little  southwest  of  Houtzdale 
northeastward.  It  has  furnished  most  of  the  coal  known  on  the  market  as  Clearfield  coal, 
and  is  still  supplying  a  large  portion  of  that  coal.  The  "D,"  or  Moshannon  seam,  as  it  is 
locally  known,  has  a  thickness  all  through  this  basin  of  from  4  to  6  feet,  running  occasionally 
much  over  the  upper  figure  and  averaging  about  5  feet.  While  the  heart  of  the  seam  in 
this  basin  has  already  been  taken,  there  is  still  some  coal  left  around  the  edges  of  the  basin 
and  in  the  center,  where  in  the  early  days  tracts  of  coal  slightly  inferior  in  thickness  or 
quality  were  passed  by.  These  remnants  are  being  rapidly  removed  by  a  large  number 
of  small  shipping  mines.  There  are  still  a  few  large  mines  operating  in  this  field,  but 
apparently  on  bodies  of  coal  which  are  fast  approaching  exhaustion. 
Bull.  285—06 18  271 
