﻿132 
  S. 
  Powers— 
  The 
  Butler 
  Salt 
  Dome. 
  

  

  Eocene 
  sandstones 
  is 
  largely 
  ahmi 
  and 
  the 
  salt 
  on 
  the 
  

   surface 
  of 
  the 
  prairies 
  is 
  probably 
  partly 
  alum. 
  

  

  But 
  these 
  conditions 
  are 
  not 
  confined 
  to 
  salt 
  domes 
  

   and 
  the 
  origin 
  of 
  the 
  salt 
  on 
  the 
  prairies 
  is 
  not 
  from 
  the 
  

   core 
  of 
  salt 
  underlying 
  the 
  center 
  of 
  the 
  dome. 
  The 
  

   water 
  is 
  artesian 
  water 
  and 
  ground 
  water. 
  A 
  number 
  

   of 
  salines 
  in 
  the 
  area 
  covered 
  by 
  the 
  Eocene 
  and 
  Oligo- 
  

   cene 
  outcrop 
  in 
  Texas 
  furnished 
  salt 
  during 
  the 
  Civil 
  

   War. 
  These 
  salines 
  are 
  characterized 
  by 
  more 
  or 
  less 
  

   circular 
  semi-barren 
  areas 
  surrounded 
  by 
  hills. 
  Abund- 
  

   ant 
  sulphur 
  and 
  other 
  springs 
  are 
  found 
  associated 
  with 
  

   them 
  as 
  well 
  as 
  natural 
  mounds, 
  blue 
  mud 
  holes, 
  and 
  cut- 
  

   off 
  lakes. 
  Among 
  their 
  number 
  may 
  be 
  mentioned 
  the 
  

   Posey 
  saline 
  in 
  Anderson 
  County, 
  the 
  Vair 
  saline 
  in 
  

   Trinity 
  County, 
  the 
  Enal 
  saline 
  in 
  Angelina 
  County. 
  

   Others 
  are 
  mapped 
  by 
  Harris. 
  4 
  Their 
  origin 
  is 
  evi- 
  

   dently 
  ascending 
  waters, 
  but 
  nowhere 
  is 
  any 
  evidence 
  of 
  

   faulting 
  or 
  of 
  uplift 
  seen. 
  

  

  Springs 
  are 
  found 
  surrounding 
  the 
  Butler 
  dome 
  on 
  the 
  

   outside 
  of 
  the 
  prairie. 
  They 
  rise 
  in 
  small 
  recesses 
  or 
  

   reentrants 
  at 
  the 
  base 
  of 
  the 
  hills. 
  As 
  there 
  is 
  no 
  evi- 
  

   dence 
  of 
  faulting 
  in 
  the 
  dome 
  and 
  as 
  a 
  single 
  horizon 
  can 
  

   be 
  traced 
  around 
  a 
  quarter 
  if 
  not 
  a 
  third 
  of 
  the 
  circum- 
  

   ference, 
  it 
  is 
  believed 
  that 
  the 
  springs 
  arise 
  from 
  one 
  or 
  

   more 
  water-bearing 
  sandstones. 
  In 
  front 
  of 
  these 
  

   springs 
  the 
  soil 
  becomes 
  soggy 
  and 
  is 
  covered 
  with 
  turf 
  

   and 
  bushes. 
  It 
  shakes 
  when 
  walked 
  on 
  and 
  a 
  heavy 
  

   weight 
  sinks 
  into 
  sand 
  underlain 
  by 
  blue 
  mud. 
  None 
  of 
  

   these 
  blue 
  mud 
  springs 
  is 
  as 
  soft 
  as 
  are 
  many 
  of 
  those 
  in 
  

   east 
  Texas 
  into 
  which 
  a 
  pole 
  can 
  be 
  pushed 
  for 
  15 
  feet 
  

   or 
  more. 
  A 
  mud 
  volcano 
  5 
  inches 
  in 
  height 
  was 
  found 
  

   near 
  one 
  of 
  the 
  springs. 
  

  

  Mounds. 
  

  

  Two 
  ways 
  in 
  which 
  natural 
  mounds 
  are 
  formed 
  may 
  

   be 
  observed 
  in 
  the 
  prairie 
  surrounding 
  the 
  dome. 
  In 
  one 
  

   case 
  the 
  springs 
  on 
  the 
  sloping 
  sides 
  of 
  the 
  prairie 
  give 
  

   rise 
  to 
  small 
  mounds 
  which 
  increase 
  in 
  height 
  with 
  the 
  

   growth 
  of 
  the 
  turf. 
  When 
  the 
  center 
  of 
  the 
  mound 
  is 
  a 
  

   foot 
  or 
  two 
  above 
  the 
  level 
  of 
  the 
  prairie 
  on 
  the 
  lower 
  

   side 
  the 
  whole 
  mass 
  begins 
  a 
  slow 
  creep 
  toward 
  the 
  

  

  4 
  Op. 
  eit., 
  pi. 
  13. 
  

  

  