﻿H. 
  E. 
  Gregory 
  — 
  Andesites 
  from 
  Maine. 
  361 
  

  

  seems 
  to 
  be 
  situated 
  along 
  a 
  fault 
  line. 
  As 
  was 
  the 
  case 
  witb 
  

   Edmund's 
  Hill, 
  so 
  here, 
  no 
  actual 
  contact 
  between 
  formations 
  

   was 
  obser\^ed, 
  but 
  the 
  sedimentaries 
  were 
  traced 
  to 
  the 
  very 
  

   base 
  of 
  the 
  hill, 
  and 
  the 
  facts 
  indicate 
  that 
  the 
  hill 
  is 
  a 
  remnant 
  

   of 
  a 
  lava 
  flow. 
  

  

  Andesites 
  of 
  South 
  Mapleton. 
  — 
  In 
  addition 
  to 
  the 
  prominent 
  

   hills 
  of 
  andesite 
  just 
  mentioned, 
  there 
  are 
  some 
  ten 
  or 
  twelve 
  

   less 
  conspicuous 
  outcrops 
  in 
  the 
  southern 
  part 
  of 
  Mapleton 
  

   township 
  crossed 
  by 
  the 
  Mapleton-Presque 
  Isle 
  road 
  and 
  

   located 
  in 
  the 
  fields 
  to 
  the 
  north 
  and 
  the 
  south 
  of 
  this 
  road. 
  

   They 
  occur 
  usually 
  as 
  narrow 
  ridges, 
  and 
  seem 
  to 
  be 
  remnants 
  

   of 
  lava 
  flows 
  which 
  occupied 
  former 
  valleys, 
  but 
  are 
  now 
  left 
  

   standing 
  because 
  of 
  the 
  erosion 
  of 
  the 
  sedimentaries 
  on 
  both 
  

   sides. 
  

  

  Andesites 
  of 
  Castle 
  Hill. 
  — 
  Castle 
  Hill 
  is 
  the 
  local 
  name 
  for 
  

   the 
  northern 
  end 
  of 
  the 
  high, 
  narrow 
  ridge 
  extending 
  N.-S. 
  

   across 
  the 
  township 
  with 
  the 
  same 
  name. 
  While 
  not 
  such 
  a 
  

   conspicuous 
  feature 
  as 
  Haystack 
  Mountain 
  at 
  the 
  southern 
  end 
  

   of 
  the 
  same 
  ridge, 
  it 
  forms 
  the 
  most 
  considerable 
  prominence 
  

   on 
  the 
  immediate 
  bank 
  of 
  the 
  Aroostook 
  River 
  along 
  which 
  

   route 
  all 
  the 
  early 
  ti'avel 
  lay, 
  and 
  hence 
  was 
  an 
  important 
  land- 
  

   mark 
  to 
  the 
  flrst 
  settlers. 
  There 
  is 
  no 
  common 
  local 
  usage 
  as 
  

   to 
  the 
  limits 
  of 
  Castle 
  Hill, 
  and 
  in 
  this 
  report 
  the 
  term 
  will 
  be 
  

   applied 
  to 
  the 
  masses 
  of 
  andesite 
  and 
  volcanic 
  elastics 
  which 
  

   lie 
  between 
  the 
  Aroostook 
  River 
  and 
  the 
  " 
  State 
  Road 
  " 
  from 
  

   Ashland 
  to 
  Presque 
  Isle. 
  It 
  covers 
  an 
  area 
  2|- 
  miles 
  long 
  

   varying 
  in 
  width 
  from 
  \ 
  to 
  f 
  mile, 
  and 
  is 
  partly 
  in 
  Castle 
  Hill 
  

   township 
  and 
  partly 
  in 
  "Wade 
  plantation. 
  The 
  wagon 
  road 
  

   crosses 
  the 
  hill 
  at 
  its 
  southern 
  end, 
  where 
  it 
  rises 
  little 
  higher 
  

   than 
  the 
  surrounding 
  plain. 
  The 
  eastern 
  side 
  has 
  a 
  gentle 
  

   slope, 
  and 
  is 
  cut 
  up 
  into 
  several 
  low 
  knobs 
  by 
  small 
  streams, 
  so 
  

   that 
  the 
  ridge 
  effect 
  is 
  not 
  apparent. 
  The 
  west 
  side 
  is 
  formed 
  

   by 
  Welt's 
  brook 
  and 
  the 
  Aroostook 
  River, 
  which 
  at 
  this 
  point 
  

   is 
  forced 
  by 
  it 
  to 
  take 
  the 
  abrupt 
  backward 
  turn 
  so 
  noticeable 
  

   on 
  the 
  map. 
  Calcareous 
  and 
  arenaceous 
  slates 
  are 
  exposed 
  in 
  

   the 
  bed 
  of 
  the 
  river, 
  while 
  a 
  short 
  distance 
  back 
  steep 
  slopes 
  

   and 
  cliffs 
  of 
  lava 
  and 
  ash 
  rise 
  to 
  a 
  height 
  of 
  several 
  hundred 
  

   feet. 
  The 
  hill 
  is 
  densely 
  wooded 
  and 
  in 
  places 
  swampy 
  except 
  

   at 
  the 
  southern 
  end 
  and 
  along 
  the 
  east 
  side. 
  At 
  these 
  points 
  

   the 
  bare 
  rocks 
  are 
  occasionally 
  exposed 
  and 
  present 
  a 
  great 
  

   variation 
  in 
  character. 
  In 
  one 
  place 
  heavy 
  ledges 
  of 
  gray 
  ande- 
  

   site 
  are 
  exposed, 
  particularly 
  on 
  the 
  knobs 
  occupying 
  the 
  

   northwest 
  and 
  southeast 
  corners 
  of 
  lot 
  3i. 
  Again 
  in 
  the 
  woods 
  

   east 
  of 
  the 
  mouth 
  of 
  Welt's 
  brook 
  is 
  an 
  outcrop 
  of 
  black 
  silici- 
  

   fied 
  tuff 
  between 
  slates. 
  On 
  the 
  southeast 
  corner 
  of 
  the 
  hill 
  

   are 
  loose 
  ash 
  beds 
  containing 
  fossils, 
  coarse 
  and 
  fine 
  volcanic 
  

   breccias, 
  and 
  pumiceous 
  lava 
  in 
  quite 
  fresh 
  condition. 
  Where 
  

  

  