WORK    ON    COAL.  205 
of  the  coal-bearing  rocks  and  the  presence  of  considerable  intrusive  material,  a  great  amount 
of  surface  wash,  and  a  heavy  covering  of  timber,  it  was  almost  impossible  to  determine  the 
areal  extent  of  metamorphism  without  thorough  prospecting  with  the  drill.  There  is  no 
doubt  that  a  good  quality  of  anthracite  occurs  in  this  area,  but  until  prospecting  has  been 
done  there  is  great  uncertainty  regarding  its  geographic  extent.  The  local  character  of 
the  metamorphism  of  the  coal  makes  it  seem  doubtful  whether  this  area  will  ever  be  of 
very  great  commercial  importance,  but  the  field  as  a  whole  is  undoubtedly  very  important, 
since  there  are  a  number  of  thick  seams  of  good  bituminous  coal  throughout  its  extent. 
This  alone  will  amply  repay  development.  Beyond  the  territory  covered  bythis  reconnais- 
sance the  coals  are  lignitic  and  of  much  poorer  grade  than  they  are  in  the  territory  surveyed. 
North  Dakota-Montana. — In  view  of  the  rather  extraordinary  results  obtained  at  the 
coal-testing  plant  in  making  producer  gas  from  brown  lignite  of  North  Dakota,  it  seemed 
desirable  to  determine  more  fully  than  heretofore  the  extent  of  such  deposits  in  North 
Dakota  and  eastern  Montana.  For  this  purpose  A.  G.  Leonard,  assisted  by  Innis  Ward 
and  II.  L.  McDonald,  made  an  examination  of  the  country  along  Little  Missouri  River, 
from  the  crossing  of  the  Northern  Pacific  Railway  into  South  Dakota.  They  also  examined 
the  territory  wTest  of  the  Little  Missouri  between  that  and  Yellowstone  River  and  up  the 
latter  stream  as  far  as  Miles  City,  obtaining  a  large  amount  of  information  on  the  occurrence 
of  workable  beds  of  lignite  and  the  general  question  of  correlation  with  other  parts  of  the 
field.  In  this  region  there  are  some  thick  beds  of  lignite,  but  they  occur  as  lenticular  masses, 
frequently  having  an  area  of  only  a  few  square  miles  and  sometimes  only  a  few  acres. 
They  are  so  common,  however,  that  almost  every  section  contains  a  bed  of  workable  thick- 
ness. The  work  done  in  this  region  shows  that  similar  conditions  prevail  over  the  western 
half  of  North  Dakota  and  a  large  area  in  the  southeast  corner  of  Montana.  At  the  present 
time  there  is  little  demand  for  these  lignites,  but  with  the  simplification  of  the  producer- 
gas  apparatus  and  gas  engine,  the  production  of  power  from  brown  lignite  will  doubtless 
be  attempted  in  many  places.  The  tests  «  show  that  in  the  producer  plant  3.47  pounds  of 
Williston  brown  lignite  were  required  to  produce  one  electrical  horsepower  per  hour,  while 
in  the  steam  plant  it  required  3.40  pounds  of  the  best  West  Virginia  steam  coal  to  produce 
the  same  result.  This  shows  that  the  brown  lignite,  though  containing  practically  40  per 
cent  of  water  as  it  was  fired  in  the  producer,  is  almost  as  valuable  for  the  production  of 
power  as  the  best  WTest  Virginia  coal  used  under  the  steam  boiler.  When  this  method  of 
production  of  power  comes  into  common  use  doubtless  it  will  bring  new  industries  into  the 
Dakota  country  and  stimulate  those  that  have  already  obtained  a  foothold.  The  lignite- 
bearing  beds  are  not  limited  to  the  area  just  described,  but  extend  indefinitely  to  the 
southwest  and  presumably  are  connected  with  the  Sheridan  field  at  the  base  of  the  Big- 
horn Mountains. 
Wyoming. — The  coal  fields  of  Wyoming  are  among  the  more  important  ones  of  the  Rocky 
Mountain  States.  Published  data  regarding  some  of  them  are  available.  Many  of  the 
others,  though  fairly  well  developed,  have  never  been  described.  This  is  the  case  of  the 
Hams  Fork  field,  which  lies  in  the  southwestern  part  of  the  State.  A  survey  of  this  inter- 
esting field  was  made  during  the  past  season  by  A.  C.  Veatch,  assisted  by  Alfred  R.  Schultz. 
That  part  of  the  coal  field  covered  by  this  survey  has  an  area  of  700  square  miles,  extending 
from  a  line  somewhat  north  of  the  Oregon  Short  Line  Railway  in  the  vicinity  of  Kemmerer 
southward  to  the  Utah  line.  Much  data  had  already  been  obtained  by  the  systematic  pros- 
pecting of  private  parties  in  the  region,  and  consequently  the  most  important  part  of 
Veatch 's  work  was  the  determination  of  the  horizons  of  the  various  coal  beds,  the  geologic 
structure,  and  the  amount  of  unclaimed  coal  lands  in  this  field.  The  report  shows  that  it  still 
contains  a  large  acreage  of  Government  land  which  can  be  entered  as  coal  lands.  A  small 
oil  field,  known  as  the  Spring  Valley  field,  was  also  thoroughly  examined  and  a  considerable 
amount  of  new  data  on  it  was  obtained. 
Utah. — Geologic  work  was  also  carried  on  in  the  coal  fields  of  Utah,  which  have  long  been 
recognized  as  among  the  most  important  in  the  West,  but  regarding  which  little  published 
"Bull.  U.  S.  Geol.  Survey  No.  261,  1905,  pp.  62,  104. 
