boutwell.]       IRON    ORES    IN    THE    UINTA    MOUNTAINS,    UTAH.  227 
which  are  breccias  made  up  of  angular  fragments  of  ore,  to  others 
which  include  barren  siliceous  gangue,  and  finally  to  those  in  which  the 
barren  country  rock  predominating  incloses  patches  of  lean  ore.  The 
following  analysis  is  of  a  selected  sample  of  the  high-grade,  massive, 
semispecular  variety. 
Analysis  of  red  iron  ore  (hematite). 
[Analyst,  E.  T.  Allen.] 
Per  cent. 
Fe  A 79. 34 
ALA 15 
Ti62 None. 
CaO None. 
MgO Trace. 
Si02 18.  55 
S None. 
P205 Trace. 
Au None. 
The  above  analysis  reveals  not  only  a  high  content  of  iron  and  a 
suitable  amount  of  silica,  but  also  a  most  desirable  absence  of  the 
deleterious  elements,  titanium  and  sulphur,  and  only  a  trace  of  phos- 
phorus. In  short,  it  indicates  a  high  grade,  workable  iron  ore.  The 
records  of  assays  of  the  lots  shipped  to  the  Park  City  smelter  in  the 
early  eighties  were  entirety  destroyed  in  the  great  tire  of  1898.  It  is 
reported  from  memory,  however,  by  T.  W.  Stringer,  custom  assayer 
at  Park  City,  Utah,  that  the  shipments  averaged  about  50  per  cent 
iron  and  5  to  20  per  cent  silica. 
Occurrence  of  ore. — The  features  shown  by  the  few  comparatively 
restricted  croppings,  together  with  those  revealed  in  the  two  small 
open  cuts,  did  not  afford  complete  evidence  as  to  the  true  nature  of  the 
occurrence  of  the  iron.  The  country  rock  is  a  gra}^  limestone.  In  the 
saddle  in  which  the  ore  has  been  worked  the  general  southerly  dip  of 
the  strata  (S.  50°  W.  10°)  passes  into  a  gentle  northerly  dip,  thus  form- 
ing a  shallow  trough.  Further,  certain  disagreements  of  dips  and 
zones  of  breccia  suggest  that  the  deformation  at  this  point  includes  not 
only  local  folding,  but  also  fracturing  and  perhaps  faulting.  The  age 
of  the  limestone  member  in  which  the  ore  is  found  is  proved  by  its 
fossil  contents  to  be  lower  Carboniferous. 
The  croppings  of  the  iron  ore,  and  thus  the  pits  which  have  been 
opened  in  them,  appear  to  lie  in  certain  fairly  distinct  easterly- westerly 
lines  or  zones.  This  fact,  in  connection  with  the  presence  of  breccia 
in  the  upper  pit,  and  the  exposure  of  a  marked  breccia  zone  in 
the  lower  pit,  suggests  that  the  ore  occurs  along  lines  and  zones  of 
fracture.  Further,  the  fact  that  the  limestones,  both  in  the  breccias 
and  in  the  country  traversed  by  the  breccias,  has  given  place  to  iron 
ore,  and  the  apparent  but  indistinct  retention  of  bedded  structure  by 
the  ore,  leads  to  the  belief  that  the  iron  ore  is  a  replacement  of  lime- 
stone in  and  adjacent  to  east-west  fracture  and  breccia  zones. 
