martin.]  PETROLEUM    FIELDS    OF    ALASKA.  373 
The  following  section  is  exposed  in  the  west  bank  of  Trout  Creek, 
2  miles  above  its  juncture  with  Stillwater  Creek,  and  6  miles  above 
the  mouth  of  the  latter: 
Section  on  Trout  Creek. 
Feet. 
Shale 4 
Coal 6| 
Sandstone 5 
The  strike  is  N.  40°  E.,  the  dip  38°  W. 
At  a  point  on  the  north  shore  of  Bering  Lake'  a  coal  seam  has  been 
exposed  which  has  a  thickness  of  about  2  feet.  The  roof  was  not  seen; 
the  floor  is  massive  sandstone. 
The  preceding  include  all  the  coal  sections  which  were  accessible 
at  the  time  the  region  was  studied;  it  is  reported,  however,  that  there 
are  many  other  seams,  some  of  them  exceeding  in  thickness  any  which 
the  writer  saw.  Two  of  these,  said  to  be  35  and  40  feet  thick,  have 
been  opened  on  the  headwaters  of  Carbon  Creek,  and  it  is  rumored  that 
a  still  thicker  seam  had  been  discovered  in  the  Stillwater  Valley  during 
the  latter  part  of  the  summer  of  1903.  Smaller  seams  have  been 
opened  on  the  shores  of  Lake  Kushakah  and  on  the  north  shore  of 
Bering  Lake. 
It  is  the  opinion  of  the  writer  that  the  foregoing  sections  represent 
distinct  coals,  and  that  furthermore,  from  the  smut  observed  by  him 
in  the  development  of  the  country,  many  additional  ones  will  be  dis- 
covered which  are  now  concealed  beneath  the  soil  and  the  dense 
vegetation. 
Owing  to  the  general  northerly  dip  throughout  the  coal  field,  the 
northern  portion  of  it,  as  at  present  recognized,  is  underlain  by  a  far 
greater  number  of  seams  than  the  southern.  The  northward  extent 
of  the  field,  however,  the  nature  of  its  structure,  and  the  manner  of 
its  termination,  remain  unknown. 
The  features  to  be  considered  by  the  mining  engineer  embrace  faults 
and  their  attendant  problems;  steep  dips;  the  physical  properties  of 
the  coal  as  affecting  its  shipment  and  market  value,  a  tendency  to  crush 
being  especially  noticeable;  the  proportion  of  the  seams  above  water 
level,  and  their  accessibility. 
CHARACTER   OF   THE    COAL. 
The  plrysical  properties  of  the  coal  are  very  much  alike  in  all  seams 
and  in  all  parts  of  the  field  seen  by  the  writer.  The  coal  resembles 
the  harder  bituminous  coals  of  the  East  more  than  it  does  anthracite. 
It  is  doubtful  if  much  of  the  coal  could  be  sized  so  as  to  compete  with 
anthracite  coal  for  domestic  use.  Under  ordinary  handling  it  will 
probably  crush  to  almost  the  same  extent  as  the  harder  grades  of  semi- 
bituminous  coal.     This  will  not,  of  course,  impair  its  value  as  a  steam 
