martin.]  PETROLEUM   FIELDS    OF    ALASKA.  367 
The  most  important  settlements  are  Kayak,  on  Little  Kayak  Island, 
which  is  the  steamer  landing  and  post-office  for  the  entire  region,  and 
the  town  of  Katalla,  at  the  mouth  of  Katalla  River.  There  are  no 
other  settlements,  except  the  camps  of  the  various  operating  com- 
panies and  several  small  Indian  villages. 
GEOLOGY. 
The  rocks  include  a  complex  semimetamorphosed  series,  a  series  of 
oil-bearing  shales,  a  series  of  coal  measures,  and  a  few  igneous  rocks. 
The  semimetamorphosed  beds  consist  of  sandstone,  limestone,  and 
shales,  which  are  well  exposed  on  the  coast  west  of  Katalla.  Fox 
Islands  and  apparently  the  extreme  southwestern  point  of  Little  Kayak 
Island  are  also  composed  of  these  rocks.  They  vary  in  color  from 
dark  gray  to  dull  tones  of  red  and  green,  and  frequently  have  a  mottled 
appearance.  They  are  usually  somewhat  crumpled,  and  do  not  carry 
an 3^  evidence  of  their  age  or  of  their  relation  to  the  other  rocks  of  the 
region. 
The  oil-bearing  shales  consist  of  a  series  of  dark  argillaceous  and 
carbonaceous  shales,  with  occasional  bands  of  sandstone,  limestone, 
conglomerate,  and  glauconitic  rock.  They  occupy  the  peninsula  be- 
tween Controller  Bay  and  Bering  Lake  and  extend  beyond  Bering 
River  to  the  east.  No  estimate  could  be  made  of  the  thickness  of 
these  shales.  The  few  fossils  which  have  been  obtained  indicate  that 
they  are  of  Tertiary  age. 
The  Coal  Measures,  which  apparently  overlie  the  oil-bearing  shales, 
consist  of  many  hundred  and  perhaps  several  thousand  feet  of  sand- 
stone and  shale,  with  many  coal  seams.  The  sandstones  are  usually 
coarse  and  are  frequently  feldspathic.  There  is  no  evidence  as  to  the 
age  of  the  formation,  except  that  the  general  structure  of  the  region 
is  such  as  to  indicate  very  strongly  that  the  Coal  Measures  overlie  the 
oil-bearing  sands,  which  are  of  an  indefinite  horizon  in  the  Tertiary. 
There  are  several  masses  of  igneous  rock  in  various  parts  of  this 
region. 
Structure. — The  structure  is  very  complex,  at  least  so  far  as  the 
minor  details  are  concerned.  There  appears  to  be  a  larger  folding, 
modified  by  a  minor  folding,  that  often  reveals  itself  merely  as  a 
crumpling  in  the  softer  shales,  but  which  is  locally  so  strongly  devel- 
oped as  to  obscure  the  major  folding.  There  are  thus  two  sets  of 
structural  features,  one  of  which  reveals  itself  in  an  east-west,  the 
other  in  a  northeast-southwest  strike.  The  first  is  well  shown  in  the 
great  anticline  which  is  described  below  as  extending  along  the  coast 
at  Cape  Yaktag,  and  again  appears  in  many  of  the  exposures  of  this 
region,  especially  along  the  coast  near  Katalla.  Of  the  second  series 
of  folds,  those  extending  in  a  direction  from  northeast  to  southwest, 
one  of  the  most  illustrative  is  the  anticline  which  apparently  extends 
