﻿1864.] 
  HONEYMAN 
  ARISAIG, 
  NOVA 
  SCOTIA. 
  335 
  

  

  other 
  to 
  the 
  Ludlow 
  Tilestone. 
  So 
  much 
  light 
  having 
  been 
  thrown 
  

   upon 
  the 
  subject 
  by 
  Mr. 
  Salter, 
  the 
  two 
  uppermost 
  and 
  the 
  lowest 
  

   members 
  of 
  the 
  series 
  having 
  been 
  determined 
  by 
  him, 
  it 
  at 
  once 
  

   occurred 
  to 
  me 
  that 
  a 
  thorough 
  examination 
  of 
  the 
  locality 
  would 
  

   now 
  be 
  sufficient 
  to 
  determine 
  what 
  still 
  remained 
  doubtful, 
  and 
  

   the 
  results 
  of 
  that 
  examination 
  I 
  now 
  beg 
  to 
  lay 
  before 
  the 
  Society. 
  

  

  § 
  2. 
  General 
  Description 
  of 
  the 
  Arisaig 
  District. 
  

  

  The 
  extreme 
  length 
  of 
  the 
  Silurian 
  rocks 
  at 
  Arisaig 
  is 
  about 
  three 
  

   and 
  a 
  half 
  miles, 
  and 
  their 
  breadth 
  three-quarters 
  of 
  a 
  mile. 
  The 
  

   group 
  is 
  thoroughly 
  representative 
  of 
  all 
  the 
  known 
  Silurian 
  locali- 
  

   ties 
  in 
  the 
  eastern 
  half 
  of 
  Nova 
  Scotia, 
  and, 
  as 
  far 
  as 
  I 
  know, 
  it 
  is 
  

   the 
  only 
  district 
  in 
  the 
  eastern 
  part 
  of 
  the 
  province 
  where 
  every 
  

   member 
  of 
  our 
  Upper 
  Silurian 
  series 
  exists 
  *. 
  Here 
  we 
  have 
  the 
  

   whole 
  in 
  an 
  apparently 
  uninterrupted 
  succession, 
  and 
  easy 
  of 
  exami- 
  

   nation, 
  much 
  of 
  it 
  being 
  exposed 
  in 
  vertical 
  and 
  horizontal 
  sections, 
  

   on 
  a 
  shore 
  subject 
  to 
  violent 
  storms, 
  accumulations 
  of 
  ice, 
  and 
  other 
  

   degrading 
  agencies. 
  It 
  is 
  also 
  bounded 
  and 
  intersected 
  to 
  a 
  con- 
  

   siderable 
  extent 
  by 
  streams, 
  two 
  of 
  which 
  rise 
  in 
  the 
  elevated 
  meta- 
  

   morphic 
  range 
  which 
  bounds 
  the 
  group 
  on 
  the 
  south. 
  The 
  general 
  

   position 
  of 
  the 
  Silurian 
  strata 
  here 
  is 
  that 
  of 
  a 
  synclinal 
  axis, 
  

   although 
  it 
  appears 
  to 
  be 
  altogether 
  different 
  from 
  any 
  of 
  Dr. 
  Daw- 
  

   son's 
  synclinal 
  and 
  anticlinal 
  folds. 
  But 
  I 
  do 
  not 
  mean 
  to 
  say 
  that 
  

   an 
  anticlinal 
  never 
  skirted 
  the 
  mountains 
  that 
  form 
  the 
  great 
  

   southern 
  boundary 
  of 
  our 
  Silurian 
  group. 
  I 
  would 
  rather 
  suppose 
  

   that 
  such 
  had 
  existed, 
  and 
  that 
  it 
  had 
  been 
  removed 
  by 
  denudation 
  

   during 
  the 
  early 
  part 
  of 
  the 
  Carboniferous 
  period. 
  Possibly 
  the 
  

   detrital 
  matter 
  resulting 
  from 
  that 
  process 
  formed 
  the 
  Lower 
  Car- 
  

   boniferous 
  conglomerate 
  which 
  we 
  find 
  associated 
  with 
  limestone 
  (D) 
  

   at 
  Doctor's 
  Brook, 
  and 
  intervening 
  between 
  the 
  said 
  mountains 
  and 
  

   a 
  considerable 
  part 
  of 
  our 
  Silurian 
  strata. 
  An 
  examination 
  of 
  the 
  

   natural 
  section 
  in 
  the 
  line 
  of 
  this 
  stream, 
  which 
  proceeds, 
  with 
  its 
  

   branches, 
  from 
  the 
  mountains, 
  and 
  traverses 
  the 
  rear 
  of 
  the 
  group, 
  

   for 
  fully 
  one 
  half 
  of 
  its 
  length, 
  in 
  a 
  deep 
  valley, 
  revealed 
  no 
  traces 
  

   whatever 
  of 
  the 
  supposed 
  old 
  anticlinal 
  axis. 
  

  

  The 
  formation 
  of 
  the 
  present 
  synclinal 
  axis 
  is 
  evidently 
  of 
  still 
  

   later 
  date, 
  these 
  strata 
  having 
  been 
  elevated 
  and 
  thrown 
  into 
  a 
  

   synclinal 
  fold 
  by 
  the 
  augitic 
  trap 
  (a 
  and 
  a', 
  fig. 
  1), 
  which 
  has 
  also 
  

   altered 
  and 
  upheaved 
  the 
  adjoining 
  Lower 
  Carboniferous 
  conglo- 
  

   merate 
  and 
  limestone. 
  

  

  The 
  trap 
  (a) 
  on 
  the 
  north, 
  or 
  shore, 
  side 
  of 
  the 
  group 
  extends 
  in 
  

   an 
  almost 
  continuous 
  line 
  from 
  Black 
  Point 
  to 
  Arisaig 
  Pier. 
  There 
  

   is 
  one 
  interruption 
  where 
  a 
  cove 
  has 
  been 
  formed, 
  and 
  where 
  the 
  

   strata 
  have 
  been 
  left 
  comparatively 
  unaltered. 
  The 
  trap-rocks 
  may 
  

  

  * 
  In 
  England 
  it 
  is 
  very 
  common 
  for 
  the 
  Llandovery 
  group 
  to 
  be 
  absent 
  ; 
  but 
  

   the 
  rarest 
  of 
  all 
  cases 
  is 
  to 
  find 
  the 
  Wenlock 
  (or 
  Niagara) 
  group 
  missing. 
  It 
  is 
  

   with 
  us 
  a 
  thicker 
  series 
  than 
  the 
  Ludlow, 
  and 
  is 
  often 
  present 
  where 
  that 
  

   is 
  altogether 
  absent. 
  See 
  Salter's 
  Report 
  on 
  the 
  Nova-Scotian 
  Silurian 
  collection. 
  

   In 
  the 
  western 
  part 
  of 
  the 
  province, 
  the 
  equivalent 
  of 
  the 
  Wenlock 
  or 
  Niagara 
  

   Limestone 
  exists, 
  according 
  to 
  Hall 
  and 
  Dawscn, 
  at 
  New 
  Canaan. 
  (Dawson's 
  

   Paper, 
  Canad. 
  Nat. 
  and 
  Geol. 
  vol. 
  v. 
  p. 
  139.) 
  

  

  2b2 
  

  

  