weed.]  HOT    SPRINGS    AND    HOT-SPRING    DEPOSITS.  003 
and  vary  in  strike  as  the  beds  curve  about  sides  of  the  anticlinal 
dome.  There  is  considerable  difference  in  elevation  along  the  veins, 
owing  to  the  relief  of  the  ground. 
The  largest  vein  is  well  exposed  on  the  steep  eastern  slopes  of  a 
little  valley  about  three-fourths  of  a  mile  west  of  the  springs.  Its 
prominent  white  outcrop  forms  in  some  places  a  wall  that  rises  3  to  6 
feet  above  the  general  surface  of  the  ground,  but  it  is  more  generally 
weathered  down  to  a  few  inches  above  the  general  surface.  The  vein 
is  almost  continuously  traceable  for  1\  miles,  from  a  point  a  mile 
south  of  the  wagon  road  to  a  point  half  a  mile  north  of  it.  In  (his 
distance  there  are  a  few  short  gaps  in  the  exposure,  in  which  debris 
and  dirt  washed  down  the  hillsides  cover  the  vein.  Throughout  this 
length  of  1J  miles  the  vein  is  remarkably  uniform  in  direction, 
though  presenting  gentle  minor  sinuosities.  The  width  varies  from 
1  to  5  feet.  The  filling  consists  mainly  of  gypsum,  which  in  weather4 
ing  breaks  along  cleavage  planes  and  presents  a  curious,  glittering 
appearance  when  seen  at  a  distance.  This  gypsum  is  seamed  by 
veinlets  of  stilbite,  which  often  form  rosette-like  masses.  Included 
fragments  of  the  gritty  sandstone  wall  rock  often  occur  in  the  vein, 
and  these  fragments  are  commonly  surrounded  by  stilbite,  resembling 
the  so-called  cockade  or  ring  ores  of  mineral  veins.  The  stilbite 
also  occurs  frequently  in  cracks  in  the  adjacent  country  rock,  form- 
ing little  veinlets  parallel  to  and  alongside  the  main  vein.  The 
only  other  mineral  seen  in  the  vein  is  calcite,  and  this  is  not  common, 
though  when  it  is  found  it  occurs  in  considerable  quantity,  but  is 
readily  distinguished  by  its  opaqueness  from  the  more  waxy-looking 
gypsum  which  surrounds  and  incloses  it.  These  reefs  are  the  most 
conspicuous  feature  of  the  country  west  of  the  hot  springs.  Their 
origin  is  clearly  to  be  ascribed  to  hot  waters,  and  the  nearest  reef  is 
about  one-fourth  of  a  mile  west  of  the  existing  springs.  So  far  as 
could  be  determined  the  veins  are  barren  of  metallic  minerals. 
The  Hunters  Hot  Springs  comprise  a  number  of  vents,  the  waters 
issuing  from  veins  similar  to  those  just  described.  The  waters  come 
from  the  central  portion  of  a  shallow  basin  inclosed  by  low  rocky 
slopes  or  bounding  walls  of  a  small  creek  valley,  whose  upper  course 
is  marked  by  groves  of  cottonwoods.  The  springs  in  the  upper 
group  issue  from  a  fissure  in  the  rocks  and  are  surrounded  by  a 
grassy  marsh.  Owing  to  artificial  excavations,  the  fissure  has  been 
exposed,  but  at  present  the  waters  are  confined  in  a  basin  or  pool 
lined  with  lumber,  the  outflow  flowing  through  a  trough  to  the  bath 
houses.  There  is  a  copious  emission  of  gas,  mainly  CG2,  but  in  part 
sulphureted  hydrogen.  The  fissure  line  is  exposed  for  a  distance  of 
perhaps  20  feet. 
The  lower  group  of  springs  issues  from  a  fissure  that  also  traverses 
the  barren  dark  purplish  sandstones  or  grits  of  the  Livingston  for- 
