Campbell]  THE    DEER    CREEK    COAL    FIELD,    ARIZONA.  253 
top  of  the  Reed  shaft,  but  this  does  not  seem  to  correspond  to  any  of 
the  beds  showing  in  the  Crowe  shaft,  and  it  is  not  known  whether  it 
has  any  representation  on  the  south  side  of  the  basin. 
Although  sufficient  prospecting*  has  not  been  done  to  determine 
clearly  the  number  of  workable  coals  in  the  basin,  it  seems  probable 
that  they  are  limited  to  two  beds,  and  the  occurrence  of  similar  expo- 
sures on  the  two  sides  of  the  field  is  fairly  good  evidence  that  the  beds 
extend  entirely  across  the  Deer  Creek  Basin. 
The  most  favorable  locality  for  developing  these  coals  is  where  the 
geologic  structure  is  the  simplest,  and  also  where  the  coals  are  the 
least  disturbed  by  dikes  and  other  intrusive  masses  of  rock,  and  also 
where  they  can  be  most  easily  reached  by  a  railroad  from  Gila  River. 
So  far  as  could  be  determined  in  the  hasty  examination  just  made,  the 
Lower  and  Middle  fields  appear  to  be  less  disturbed  by  complicated 
folding  than  the  Upper  field,  consequently  the  coal  is  better  disposed 
for  economical  mining.  The  coals  in  the  Upper  field  make  a  larger 
showing  at  the  surface,  but,  according  to  the  present  interpretation, 
this  is  due  to  minor  folds,  and  these  would  be  extremely  troublesome 
in  commercial  mining. 
All  parts  of  the  field  are  much  disturbed  by  igneous  dikes  and  the 
three  fields  in  question  have  suffered  about  equally  in  this  respect. 
With  regard  to  transportation  facilities  the  Lower  field  has  a  decided 
advantage,  since  the  surface  of  the  basin  in  this  field  is  comparatively 
flat  and  not  diversified  by  any  marked  hills  or  sharp  and  deeply  cut 
valleys.  It  is  also  considerably  nearer  Gila  River  and  could  be  much 
more  easily  reached  by  a  line  of  railroad  than  could  either  the  Middle 
or  the  Upper  field. 
The  Lower  field  is  divided  into  two  parts  by  an  extensive  dike  which 
trends  nearly  east  and  west,  and  presumably  extended  from  an  igneous 
outflow  in  the  knobs  east  of  the  Reed  mine.  Along  this  dike  there 
has  been  considerable  disturbance  of  the  adjacent  rocks,  and  this  region 
should  be  avoided  in  the  development  of  the  field.  There  is,  however, 
a  large  area  to  the  north  of  this  dike  in  which  the  coal  can  probably 
be  found  within  a  distance  of  100  to  200  feet  of  the  surface  and  in  which 
the  rocks  are  comparatively  undisturbed.  Also  the  region  south  of 
the  dike  in  the  center  of  the  basin  offers  promising  territory  for  the 
development  of  mines.  Only  two  small  dikes  were  observed  between 
the  large  dike  just  mentioned  and  Deer  Creek.  These  dikes  are  of 
small  dimensions  and  probably  do  not  extend  for  a  very  great  distance. 
With  the  present  information  it  is  impossible  to  say  at  what  depth  the 
coal  occurs  below  the  surface  in  the  center  of  the  basin,  but  it  seems 
probable  that  nowhere  does  it  exceed  600  to  700  feet. 
QUALITY   OF   COAL. 
Owing  to  the  large  amount  of  impurities  in  this  coal  it  is  of  a 
comparatively  low  grade,  and  if  the  field  were  more  favorably  located 
