218         CONTRIBUTIONS    TO    ECONOMIC    GEOLOGY,    1907,    PART   II. 
variety,  which  closely  approach  the  bituminous  class.  The  coal 
usually  cleaves  in  small  blocks  and  at  some  places  breaks  into  prisms, 
but  weathering  generally  develops  a  platy  structure  along  the  bed- 
ding planes.  This  coal  does  not  stock  well,  and  is  therefore  placed 
below  the  bituminous  class,  though  in  heat  value  it  approaches  some 
of  the  bituminous  coals  of  the  Mississippi  Valley. 
The  heat  value  of  three  of  the  coals  given  in  the  above  table  falls 
below  10,000  British  thermal  units.  This  low  heat  value  is  probably 
due  to  the  high  ash  or  moisture  content  and  not  to  the  quality  of  the 
coal,  and  therefore  these  three  coals  should  be  classed  like  the  others. 
The  coal  ignites  readily  and  burns  freely.  It  gives  a  quick  but  not  a 
long-continued  heat  and  is  adapted  to  general  use,  especially  for 
domestic  purposes.  Analyses  of  coals  from  adjacent  regions,  by 
which  comparison  may  be  made,  are  given  by  other  writers  in  this 
volume. 
MARKET.  % 
The  market  for  the  Bighorn  Basin  coal  fields  is  and  probably  will 
remain  in  the  railroads  of  the  region  and  the  agricultural  areas  where 
irrigation  is  carried  on.  At  present  large  tracts  of  land  are  being  irri- 
gated in  the  Bighorn  Basin,  and  the  area  of  irrigation  is  rapidly  ex- 
tending. The  United  States  Reclamation  Service  is  now  engaged  on 
an  extensive  project  at  Cody  which  will  bring  a  large  tract  of  land 
under  cultivation  by  people  who  will  demand  fuel  for  many  months 
each  year.  Private  companies  are  planning  to  construct  extensive 
irrigation  works,  which  are  attracting  settlers.  These  various  settle- 
ments will  increase  the  demand  for  domestic  fuel,  which  will  prob- 
ably be  supplied  from  the  mines  in  the  field.  The  railroads  of  the 
basin  will  probably  draw  on  the  mines  for  a  constant  supply.  There 
are  .no  large  cities  with  extensive  manufacturing  plants  in  the 
area,  nor  is  there  promise  of  any  being  established  in  the  immediate 
future.  Any  estimate  of  the  production  of  the  fields  at  the  present 
time  can  not  be  fairly  representative,  for  the  southeastern  held  is 
rapidly  developing. 
FUTURE   DEVELOPMENT. 
These  coal  fields  have  a  very  promising  future.  During  the  fall  of 
1907  the  Gebo  field  was  entered  by  the  southern  extension  of  the  Bur- 
lington Railroad  to  Kirby  station,  where  the  mines  of  the  Gebo  dis- 
trict are  being  rapidly  developed.  A  branch  of  the  same  railway 
reaches  Cody,  but  in  that  vicinity  there  are  no  coal  beds  which  prom- 
ise extensive  development.  The  Grass  Creek  and  Meeteetse  are  two 
very  promising  fields  which  remain  without  railway  facilities,  hence 
