﻿134 
  S. 
  Poivers—The 
  Butler 
  Salt 
  Dome. 
  

  

  part 
  Midway. 
  "Within 
  the 
  prairie 
  the 
  outer 
  rim 
  of 
  h 
  r 
  3 
  

   is 
  composed 
  of 
  blue 
  shales 
  with 
  lenses 
  of 
  limonite 
  .nd 
  

   siderite 
  concretions 
  in 
  which 
  fossils 
  of 
  Midway 
  (* 
  age 
  

   were 
  collected. 
  Directly 
  underlying 
  these 
  beds 
  ai 
  simi- 
  

   lar 
  shales 
  of 
  blue 
  color 
  practically 
  free 
  from 
  limonite 
  in 
  

   which 
  Upper 
  Cretaceous 
  fossils 
  were 
  found. 
  

  

  There 
  is 
  a 
  greater 
  uniformity 
  of 
  beds 
  and 
  absence 
  of 
  

   faulting 
  in 
  this 
  dome 
  than 
  in 
  either 
  of 
  the 
  domes 
  of 
  

   Anderson 
  County. 
  The 
  beds 
  dip 
  quaquaversally 
  from 
  

   the 
  dome 
  at 
  angles 
  ranging 
  from 
  70° 
  near 
  the 
  salt 
  core 
  

   to 
  horizontal 
  3000 
  feet 
  away 
  from 
  its 
  edge. 
  There 
  is 
  

   probably 
  an 
  unconformity 
  between 
  the 
  Wilcox 
  and 
  

   Mount 
  Selman 
  formations 
  as 
  described 
  below. 
  A 
  de- 
  

   scription 
  of 
  outcrops 
  follows. 
  

  

  On 
  the 
  west 
  side 
  of 
  Burton 
  Hollow 
  from 
  the 
  north 
  

   proceeding 
  south 
  the 
  first 
  exposure 
  is 
  shale, 
  of 
  yellowish 
  

   color 
  when 
  weathered, 
  with 
  concretionary 
  beds 
  of 
  limon- 
  

   ite. 
  In 
  the 
  east-west 
  road 
  sandy 
  shales 
  and 
  sands 
  of 
  

   yellow 
  and 
  grey 
  color 
  and 
  shales 
  of 
  chocolate 
  color 
  are 
  

   exposed. 
  The 
  thin 
  beds 
  are 
  separated 
  by 
  heavy 
  beds 
  of 
  

   limonite. 
  In 
  a 
  small 
  lateral 
  gully 
  farther 
  south 
  there 
  

   are 
  sandy 
  clays 
  of 
  lavender 
  to 
  grey 
  color, 
  probably 
  

   stained 
  by 
  the 
  weathering 
  of 
  lignite. 
  Above 
  them 
  is 
  a 
  

   shale 
  pebble 
  conglomerate 
  composed 
  of 
  pebbles 
  of 
  grey 
  

   color 
  1 
  inch 
  to 
  4 
  inches 
  in 
  length 
  crowded 
  together 
  in 
  a 
  

   bright 
  yellow 
  sand 
  matrix. 
  Similar 
  conglomerates 
  have 
  

   been 
  found 
  by 
  the 
  writer 
  in 
  the 
  Wilcox 
  formation 
  in 
  four 
  

   localities 
  in 
  the 
  western 
  portion 
  of 
  Freestone 
  County; 
  

   in 
  a 
  creek 
  which 
  crosses 
  the 
  "south" 
  Jewett 
  road 
  2 
  miles 
  

   southwest 
  of 
  Donie, 
  on 
  the 
  BBB. 
  & 
  C. 
  RR. 
  survey; 
  in 
  a 
  

   cut 
  at 
  mile 
  post 
  200 
  on 
  the 
  Trinity 
  and 
  Brazos 
  Valley 
  

   Eailroad, 
  iy 
  2 
  miles 
  north 
  of 
  Freestone; 
  and 
  in 
  a 
  small 
  

   creek 
  which 
  crosses 
  the 
  Teague-Fairfield 
  road 
  4 
  miles 
  

   from 
  Teague. 
  They 
  are 
  not 
  uncommon 
  in 
  both 
  the 
  Wil- 
  

   cox 
  and 
  Mount 
  Selman 
  formations. 
  

  

  The 
  gully 
  farthest 
  south 
  on 
  the 
  west 
  side 
  of 
  the 
  Hollow 
  

   shows 
  typical 
  Wilcox 
  sand 
  of 
  red, 
  dull 
  yellow, 
  and 
  grey 
  

   color 
  with 
  occasional 
  limonitic 
  partings. 
  

  

  The 
  most 
  readily 
  traced 
  horizon 
  on 
  the 
  southwest 
  side 
  

   of 
  the 
  dome 
  is 
  found 
  on 
  the 
  east 
  side 
  of 
  the 
  Hollow. 
  

   Rows 
  of 
  sideritic 
  concretions 
  dipping 
  70 
  degrees 
  west 
  

   are 
  exposed 
  above 
  beds 
  of 
  plastic 
  blue 
  clay 
  at 
  the 
  south 
  

   side 
  of 
  the 
  north 
  road 
  to 
  Butler. 
  The 
  larger 
  concre- 
  

  

  