68  CONTRIBUTIONS   TO    ECONOMIC    GEOLOGY,   1907,   PART   II. 
about  140  feet  above  the  Wildhorse  bed.  This  is  a  very  erratic  bed, 
but  in  places  reaches  considerable  thickness  and  appears  to  be  of  good 
quality.  Its  outcrop  roughly  follows  that  of  the  Wildhorse  coal, 
throughout  T.  5  N.,  R.  27  E.,  lying  to  the  north  of  that  bed.  It  con- 
tinues farther  west  than  the  Wildhorse,  cutting  across  the  northeast 
corner  of  T.  5  N.,  R.  26  E.  Near  the  center  of  the  northern  boundary 
of  T.  5  N.,  R.  26  E.,  it  shows  its  greatest  thickness  of  more  than  6  feet, 
but  within  a  mile  to  the  southwest  it  thins  to  a  feather  edge.  It  is 
extremely  irregular  in  thickness  in  certain  portions  of  the  field,  but 
may  be  said  to  average  about  3  feet.  This  coal  bed  is  characterized 
by  one  or  two  partings  near  the  middle,  as  shown  in  the  following 
representative  section  : 
Section  of  Buclccy  coal  bed  in  sec.  20,  T.  5  N.,  R.  27  E. 
Ft.     in. 
Coal 6 
Coal  and  shale 6 
Coal 1      1 
Shale 6 
Coal 2      4 
4     11 
Above  the  Buckey  coal  the  rocks  are  practically  barren  of  coal  beds 
for  a  distance  of  200  feet  to  the  Dorrity  coal.  This  is  a  very  persist- 
ent bed,  uniform  both  in  thickness  and  quality.  It  extends  through- 
out Rs.  26  and  27,  occurring  along  the  northern  border  of  T.  5  N., 
R.  27  E.,  and  in  the  southern  part  of  T.  6  N.,  R.  26  E.  It  lies  to  the 
south  of  the  outcrop  of  the  Mammoth  bed  and  is  about  200  feet  below 
the  latter  in  the  stratigraphic  column.  (See  PI.  IV.)  The  thickness 
of  the  Dorrity  coal  bed  ranges  between  2  and  3  feet.  On  the  eastern 
edge  of  T.  6  N.,  R.  26  E.,  like  most  of  the  other  coals,  it  thins  to  less 
than  2  feet.     The  following  section  is  representative  of  this  coal  bed: 
Section  of  Dorrity  coal  bed  in  sec.  36,  T.  6  N.,  R.  26  E. 
Ft.  in. 
Coal  with  bony  layers 9 
Coal 1  11 
Between  this  coal  bed  and  the  Mammoth  bed  above  there  are  two 
or  more  thin  beds  of  coal  which  in  places  may  reach  2  feet  in  thick- 
ness. The  most  important  of  these,  the  Pompey  coal,  occurs  110 
feet  above  the  Dorrity  and  is  most  prominent  along  the  northern 
border  of  T.  5  N.,  R.  27  E.,  and  in  the  southeast-central  part  of 
T.  6  N.,  R.  26  E.  (L  coal,  PL  IV).  It  is,  however,  very  irregular, 
and  in  many  places  its  value  is  utterly  destroyed  by  partings;  conse- 
quently it  does  not  deserve  further  description. 
The  Mammoth  bed  is  the  most  important  coal  in  the  region  studied 
(K  coal,  PL  IV),  presenting  a  greater  thickness  than  any  other  bed. 
