CONTRIBUTIONS    TO    ECONOMIC    GEOLOGY,  1905. 
Section  of  coal  beds  in  tht  mesa  1  milt  north  oj  Chico  Arroyo,  about  16  miles  west  ofCabe&M 
N.Mex. 
Ft.  In. 
Alternating  beds  of  sandstone  ana"  shale 20 
Shale,  brown,  carbonaceous -    5 
Coal 3    3 
Shale,  brown,  carbonaceous 2 
Shale 20 
Coal 1 
Sai  H  1st  one 20 
Coal 1 
Section  of  coal  beds  thro  -fourths  of  a  milt  north  of  the  Cabezon-San  Mateo  road,'2->  miles  from 
Cabezon,  N.  Mex. 
Ft.  In. 
Shal''.  arenaceous 5 
Coal l 
Shalr.  brow  n,  carbonaceous 0 
Sandstone  and  shale  interbedded 8 
Shale,  brown,  carbonaceous 2 
Coal , 2     0 
Shale  brown,  carbonaceous. 
Section  oj  root  !><</  ~>  miles  north  oj  Alesna  Peak,  New  Mexico. 
Ft.  In. 
Shale,  biow  ii.  carbonaceous. 
Coal 2    (i 
Section  of  rout  bed  in  arroyo  .",  miles  north  oj  tht  Cabezon-San  Mateo  road  and  5  miles  westM 
southwest  of  Alesna  Peak,  New  Mexico. 
Ft. 
Shale. 
Coal,  with  thin,  bony  partings  near  top  and  middle 5 
Shale. 
No  <le\  elopmenl  has  been  undertaken  in  this  disl  rict.  The  coal  is  a  good  grade  of  Mack 
lignite  and  in  appearance  compares  favorably  with  the  Carbonero  coal  and  with  that  of 
Gallup  and  Fruitland,  to  be  described  later.  It  is  probably  of  workable  thickness  through- 
..in  an  area  of  at  least  o<><>  square  miles. 
BOSTA    BUTTE    DISTRICT. 
The  Hosta  But  te  disl  rict  extends  north  of  wesl  from  San  Mateo  and  Mount  Taylor  across 
the  continental  divide  nearly  to  Gallup,  a  distance  of  about  60  miles.  It  lies  about  12  miles 
north  of  the  Atchison.  Topeka  and  Santa  Fe  Railway,  and  contains  three  groups  of  coal 
hearing  rock-,  upper,  middle,  and  lower. 
The  upper  coal  group  was  observed  only  in  the  northwestern  part  of  the  district,  in  the 
southeast  corner  of  the  Navajo  Indian  Reservation,  where  it  has  an  extent  of  about  .'$() 
miles  in  an  east-west  direction.  From  the  similarity  of  its  beds  it  is  correlated  with  the 
upper  coal  group  of  the  <  hico  Arroyo  district,  which  has  been  referred  to  the  upper  part  ofl 
the  Montana,  and  with  which  the  beds  probably  connect  beneath  the  plain  along  the  nortl 
border  of  the  Hosta  Butte  dist  rict .  Owing  to  scarcity  of  outcrops,  however,  this  connection 
has  not  been  t  raced.  The  beds  of  this  dist  rid  also  seem  to  connect  with  those  at  Gallup] 
to  be  described  later,  and  it  is  also  probable  thai  they  hear  the  coal  reported  to  occur  'M) 
to  40  miles  north  of  the  Hosta  Butte  district  out  in  the  basin,  at  Stony  Butte  and  beyond 
Rio  Chaco. 
The  middle  and  lower  coal  groups  enter  the  Hosta  Butte  district  from  the  direction  of 
Mount  Taylor  and,  after  extending  northwestward  across  the  district,  curve  southward  and 
form  the  hogback,  which  crosses  the  railroad  3  miles  east  of  Gallup.  Their  geologic  age  is 
not  definitely  determined,  but  from  the  evidence  of  a  few  fossils  collected  in  each  of  them 
it  is  probable  that  the  middle  group  represents  the  lower  part  of  the  Montana  formation  and 
that  the  lower  group  represents  a  part  of  the  Colorado  formation. 
