COAL  IN  NORTHWESTERN  COLORADO  AND  NORTHEASTERN  UTAH.       307 
to  the  arim  rock"  of  Haven  Park.  This  ridge  is  very  distinct  and 
easily  traced  to  and  beyond  Green  River  and  the  position  of  the 
Mesaverde  coal  beds  may  be  inferred  from  it,  even  where  they  are  not 
actually  exposed.  As  a  whole,  however,  the  Mesaverde  formation  is 
relatively  much  thinner  in  Utah  than  in  Colorado,  and  the  thinning 
is  apparently  due  to  the  absence  of  upper  members  of  the  formation 
which  are  represented  elsewhere.  Thus  the  Wasatch  strata  uncon- 
formable overlying  the  Mesaverde  appear  to  sink  deeper  and  deeper 
as  they  are  traced  to  the  west.  The  coal  beds  that  are  commonly 
found  in  the  upper  part  of  the  Mesaverde  formation  in  other  fields 
are  probably  wanting  here.  The  whole  formation,  which  measures 
approximately  5,000  feet  in  the  Grand  Hogback  field  and  2,500  feet 
on  Red  Wash  in  Colorado,  is  probably  not  more  than  1,500  feet 
thick  and  possibly  less  near  Green  River.  In  each  place  the  section 
toward  the  base  of  the  formation  appears  to  remain  practically  con- 
stant, but  the  upper  beds  are  beveled  off,  disappearing  one  by  one 
toward  the  west. 
Local  development  of  the  Mesaverde  coal. — Coal  is  exposed  from  place 
to  place  along  these  outcrops,  and  has  been  mined  to  a  small  extent. 
A  bed  of  coal  at  least  7  feet  thick  and  possibly  thicker  has  been  opened 
in  a  gulch  about  2  miles  south  of  "Cocklebur,"  in  T.  6  S.,  R.  24  E., 
of  the  Salt  Lake  base  and  meridian,  and  a  slope  has  been  run  in  on  the 
dip  of  the  strata,  which  is  35°  at  this  place.  The  mine  is  9  or  10 
miles  from  the  ferry  at  Jensen,  on  Green  River,  which  is  the  nearest 
present  market  for  the  coal.  The  product  appears  to  be  a  very  good 
grade  of  bituminous  coal,  well  suited  for  domestic  use,  but  a  poor 
road  for  hauling  has  probably  hindered  the  development  of  the  mine. 
West  of  Green  River  several  attempts  have  been  made  to  mine  the 
Mesaverde,  coal,  but  at  present  all  these  operations  are  abandoned. 
An  old  mine  in  T.  5  S.,  R.  22  E.,  is  situated  on  the  northeast  side  of 
a  small  isolated  knob  on  the  western  side  of  the  valley  lands.  This 
is  said  to  have  been  opened  in  1893  and  worked  at  intervals  until 
about  1904.  The  coal  bed  is  reported  to  have  broken  off  at  the  face, 
probably  along  a  local  fault  or  slump.  The  coal  at  present  exposed 
is  3  feet  5  inches  thick,  but  the  whole  bed  is  reported  to  have  been 
about  5  feet  as  worked.  This  coal  has  the  smell  of  asphaltum  or 
oil,  and  as  it  occurs  just  below  the  outcrop  of  an  asphaltum  deposit, 
that  material  has  very  probably  saturated  the  coal  as  it  has  much  of 
the  neighboring  rock.  The  coal  is  said  to  have  caked  somewhat  when 
burned,  spreading  over  the  grates  and  forming  a  heavy  clinker,  a 
property  possibly  due  to  the  asphaltum  it  contains.  It  is  also 
reported  to  have  slacked  rapidly — within  a  month  after  taken.from 
the  mine — if  left  in  the  open  air. 
Another  prospect  about  3  miles  southwest  of  Vernal  exposed  a 
small  bed  of  coal  which  did  not  appear  to  be  of  much  importance. 
