232 
CONTRIBUTIONS    TO    ECONOMIC    GEOLOGY,   1903. 
[BULL.  225. 
hematite  and  magnetite  is  chalcedonic  and  crystalline  quartz,  which 
has  been  deposited  as  vein  material  in  numerous  minute  cavities,  some- 
times completely  filling-  them,  but  more  often  not.  The  chalcedonic 
quartz  is  in  characteristic  dense,  opaque,  white,  gray,  bluish,  or  pur- 
plish masses,  which  in  cavities  present  mammillary  surfaces.  Not 
infrequently  the  crystalline  quartz  has  a  purple  color  for  a  fraction  of 
an  inch  immediately  adjacent  to  the  iron  oxide.  Well-developed 
quartz  crystals  project  into  the  cavities.  Crystals  of  apatite  occasion- 
ally penetrate  the  ore,  and  in  the  veins  at  the  Great  Western  mine 
above  mentioned  cross  partially  filled  cavities. 
Much  of  the  ore  that  has  been  reached  by  test  pits  and  shafts,  and 
especially  that  beneath  and  in  immediate  contact  with  the  limestone, 
is  a  somewhat  soft,  earthy,  red  hematite  containing  much  magnetite. 
This  may  be  well  seen  in  one  of  the  shafts  of  the  Pinto  group  and  in 
numerous  test  pits  on  Desert  Mound. 
Analyses  of  the  ore  published  in  Volume  III  of  Lieutenant  Wheeler's 
report  on  Explorations  and  Surveys  West  of  the  One-hundredth  Merid- 
ian and  in  Putnam's  report  in  the  Tenth  Census  indicate  a  content  of 
metallic  iron  ranging  from  39  to  68  per  cent,  and  phosphorus  com- 
monly above  the  Bessemer  limit.  Commercial  analyses  made  in  recent 
years  from  samples  carefully  selected  for  the  purpose  of  determining 
the  composition  of  the  ore  in  the  large  quantities  in  which  it  would 
have  to  be  mined  give  for  the  most  part  results  intermediate  between 
the  extremes  above  noted.  Twenty-one  analyses  by  Harry  L.  Brinker, 
each  of  them  representing  a  considerable  area,  show  a  range  in  com- 
position as  follows: 
Range  in  composition  of  ore  of  southern  Utah,  as  shown  by  21  analyses. 
Iron,  metallic 
Silica 
Sulphur 
Phosphorus . . 
Manganese  . . 
Lime 
Magnesia 
Copper 
Range. 
Per  cent. 
Per  cent. 
46.78    to  67.  98 
58.  54 
2.57    to  19.74 
8.29 
.  029  to      .  224 
.082 
.029  to    1.134 
.185 
.02    to      .58 
.118 
.779  to    6.33 
2.71 
.47    to    3.76 
1.77 
.  002  to      .  151 
.027 
Average. 
Ninety-five  analyses  by  Lerch  Brothers  from  average  samples  from 
'  claims,  in  all  parts  of  the   district,  but  especially  in  the  southern 
37  claims,  in  all  parts  of  the  district,  but  especiall; 
portion,  show  the  following  range  and  average: 
