74  CONTRIBUTIONS    TO    ECONOMIC    GEOLOGY,  1906,  PART    I. 
tinuation  of  the  Absaroka  fault,  which  here  lies  along  the  east  base  of 
the  Salt  River  Range.  The  displacement  along  this  fault  is  about  the 
same  as  in  the  south  end  of  this  area.  The  Salt  River  Range  has  been 
uplifted  and  its  component  rocks  thrown  into  the  sharpest  folds.  As 
most  of  the  range  lies  west  of  this  area,  no  detailed  sections  were  made 
across  it,  but  very  probably  the  same  type  of  structure  exists  here 
as  in  the  Hoback  Range.  The  faulted  anticline  (3)  gives  rise  to  the 
Wyoming  Range,  and  the  fault  extends  approximately  along  the 
eastern  base  of  the  range  in  much  the  same  manner  as  the  Absaroka 
fault  along  the  Salt  River  Range.  These  two  faults  are  connected  by 
a  cross  fault  in  which  the  downthrow  is  on  the  south,  with  a  displace- 
ment of  about  5,000  feet.  Near  the  south  end  of  the  Wyoming 
Range  two  or  more  secondary  folds  are  developed. 
MINING    DEVELOPMENTS. 
GOLD    IN    Till:    ROCKS. 
The  gold  that  has  thus  far  been  reported  lies  in  the  northern  third 
of  the  area  above  described.  The  reported  gold  on  the  east  side  of  the 
Wyoming  Range  occurs  in  sedimentary  rocks  of  Jurassic  age.  The 
only  prospecting  that  has  been  done  is  in  the  vicinity  of  Horse  Creek, 
in  T.34  N.,R.  114  and  115  W.  Numerous  claims  have  been  staked  outi 
along  this  creek,  but  thus  far  practically  no  development  work  has 
been  carried  on.  A  few  shallow  pits  have  been  opened  on  both  sides  oft 
the  creek.  Some  of  these  pits  were  visited  by  E.  E.  Smith  and^the 
writer  last  summer,  but  no  indications  of  gold  were  visible.  It  is- 
reported  locally  by  persons  who  are  interested  in  the  claims  that  sev- 
eral assays  of  the  rock  on  Horse  Creek  show  high  values  in  gold  and 
silver.  Among  the  best  was  a  sample  taken  from  the  ledge  on  Wesley 
Vickery's  claim,  where  the  rock  is  said  to  assay  as  high  as  $66  per  ton 
in  gold  and  a  maximum  of  about  $18  per  ton  in  silver.  This  claim 
was  not  visited  nor  any  of  the  rock  samples  seen  by  members  of  this 
party  while  on  Horse  Creek,  but  the  sample  sent  by  Mr.  Vickery  from 
his  10-foot  tunnel  looks  promising,  and  if  much  such  came  from  this 
vicinity  it  would  certainly  jusl  ify  further  development.  The  Jurassic 
rocks  here  consist  of  bluish-gray  shales  and  limestones,  with  some 
gray  and  yellow  sandstone  interbedded  with  dark-gray  shales.  They 
lie  on  the  west  side  of  the  anticlinal  fold  and  the  beds  dip  toward  the 
west  at  angles  of  30°  to  45°.  On  the  north  side  of  Horse  Creek  the 
strike  turns  abruptly  and  continues  N.  40°  W.  approximately  along 
the  trend  of  the  stream  which  here  follows  the  outcrop  of  the  Benton 
shale.  In  this  locality  the  Jurassic  beds  are  slightly  brecciated  and 
contain  numerous  small  seams  of  calcite.  Some  of  the  rock  shows 
considerable  iron  pyrite,  and  in  many  places  iron  stains  are  associated 
with  the  calcite  cavities.     The  claims  are  by  no  means  restricted  to 
