﻿1864.] 
  HONEYMAN 
  ARISAIG, 
  NOVA 
  SCOTIA. 
  339 
  

  

  already 
  been 
  observed. 
  It 
  is 
  obscure 
  where 
  we 
  might 
  have 
  expected 
  

   to 
  find 
  a 
  repetition 
  of 
  B 
  and 
  A. 
  Those 
  formations 
  only 
  appear 
  on 
  

   this 
  side 
  of 
  the 
  synclinal, 
  at 
  the 
  eastern 
  part 
  of 
  Doctor's 
  Brook, 
  

   where 
  its 
  course 
  is 
  north 
  and 
  south. 
  

  

  We 
  have 
  now 
  reached 
  the 
  boundary 
  of 
  the 
  Silurian 
  formation, 
  

   and 
  the 
  section 
  next 
  passes 
  through 
  E, 
  which 
  is 
  Lower 
  Carboni- 
  

   ferous. 
  Here 
  we 
  have, 
  first, 
  compact 
  limestone, 
  and 
  then 
  hardened 
  

   conglomerate, 
  raised 
  to 
  a 
  considerable 
  elevation 
  by 
  an 
  equally 
  

   elevated 
  mass 
  of 
  trap 
  (a'), 
  which 
  succeeds 
  it. 
  This 
  trap 
  is 
  pervaded 
  

   by 
  numerous 
  veins 
  of 
  specular 
  iron-ore, 
  which 
  are, 
  however, 
  too 
  

   small 
  to 
  be 
  of 
  any 
  economical 
  value 
  ; 
  succeeding 
  this 
  trap 
  is 
  (6) 
  the 
  

   syenite 
  of 
  the 
  mountain-range. 
  

  

  § 
  4. 
  Section 
  from 
  the 
  East 
  of 
  Arisaig 
  Pier 
  to 
  Doctor's 
  Brook. 
  

  

  The 
  next 
  section 
  (fig. 
  3) 
  begins 
  at 
  a 
  point 
  east 
  of 
  Arisaig 
  Pier, 
  and, 
  

   after 
  it 
  reaches 
  the 
  south 
  side 
  of 
  the 
  harbour, 
  its 
  course 
  is 
  due 
  south 
  

   until 
  it 
  reaches 
  Doctor's 
  Brook 
  Valley 
  ; 
  it 
  then 
  passes 
  on, 
  and 
  meets 
  

   Doctor's 
  Brook 
  in 
  the 
  mountain. 
  This 
  section 
  is 
  very 
  interesting, 
  

   as 
  it 
  unquestionably 
  passes 
  through 
  the 
  whole 
  group, 
  and 
  as 
  there 
  

   is 
  very 
  little 
  uncertainty 
  in 
  the 
  course 
  which 
  it 
  traverses. 
  We 
  have 
  

   first 
  (a) 
  a 
  part 
  of 
  the 
  line 
  of 
  trap, 
  which 
  is 
  here 
  amygdaloid. 
  

   Succeeding 
  this 
  is 
  an 
  elevated 
  mass 
  of 
  (A) 
  the 
  equivalent 
  of 
  the 
  

   Mayhill 
  sandstone, 
  which 
  has 
  been 
  very 
  much 
  altered 
  by 
  the 
  trap. 
  

   It 
  is 
  now 
  a 
  rock 
  of 
  porcellanous 
  jasper, 
  having 
  often 
  a 
  beautiful 
  

   riband-like 
  appearance. 
  To 
  the 
  westward 
  are 
  the 
  pier-rocks, 
  con- 
  

   sisting 
  of 
  an 
  elevated 
  mass 
  of 
  A, 
  in 
  like 
  manner 
  converted 
  into 
  a 
  

   jaspideous 
  rock, 
  and 
  of 
  a 
  great 
  mass 
  of 
  trap 
  lying 
  on 
  the 
  south-east 
  

   of 
  the 
  former. 
  Between 
  the 
  trap 
  of 
  the 
  point 
  of 
  section 
  and 
  this 
  

   there 
  is 
  a 
  break, 
  opposite 
  to 
  which 
  we 
  have 
  strata 
  of 
  the 
  group 
  A, 
  

   very 
  little 
  altered, 
  consisting^of 
  la) 
  r 
  ers 
  of 
  red 
  and 
  yellow 
  sandy 
  shale, 
  

   evidently 
  similar 
  to 
  the 
  strata 
  which 
  on 
  either 
  side 
  have 
  been 
  con- 
  

   verted 
  into 
  jaspideous 
  rock 
  ; 
  after 
  these 
  we 
  have 
  a 
  low 
  section 
  of 
  the 
  

   group 
  B; 
  this 
  is 
  the 
  continuation 
  of 
  the 
  black 
  laminated 
  and 
  concre- 
  

   tionary 
  shale, 
  with 
  Lingulce 
  and 
  Graptolites, 
  already 
  referred 
  to. 
  At 
  

   ebb-tide 
  we 
  find 
  this 
  shale 
  continued 
  farther 
  on 
  the 
  shore 
  at 
  the 
  

   mouth 
  of 
  Arisaig 
  Brook, 
  on 
  ascending 
  which 
  it 
  is 
  seen 
  exposed 
  in 
  an 
  

   interesting 
  manner 
  on 
  the 
  sides 
  and 
  bottom 
  of 
  the 
  brook, 
  being 
  here 
  

   black 
  and 
  ferruginous, 
  and 
  apparently 
  destitute 
  of 
  organisms. 
  This 
  

   passes 
  into 
  the 
  group 
  B', 
  where 
  the 
  ground 
  becomes 
  elevated, 
  the 
  

   strata 
  at 
  the 
  mill 
  showing 
  many 
  specimens 
  of 
  a 
  characteristic 
  Orthis, 
  

   associated 
  with 
  Graptolithus 
  CUntonensis 
  (?), 
  Hall. 
  The 
  passage 
  

   from 
  B 
  to 
  B' 
  is 
  very 
  apparent 
  here, 
  as 
  well 
  as 
  at 
  Doctor's 
  Brook. 
  

   The 
  shale 
  of 
  B' 
  is 
  more 
  compact 
  than 
  that 
  of 
  B 
  ; 
  it 
  is 
  less 
  ferruginous, 
  

   being 
  generally 
  of 
  a 
  lighter 
  colour, 
  and 
  it 
  was 
  probably 
  deposited 
  

   under 
  conditions 
  more 
  favourable 
  than 
  the 
  other 
  for 
  the 
  existence 
  

   of 
  life. 
  

  

  The 
  foregoing 
  observations 
  are 
  of 
  interest 
  as 
  they 
  demonstrate 
  the 
  

   sequence, 
  hitherto 
  unknown, 
  of 
  the 
  lowest 
  members 
  of 
  the 
  series, 
  

   and 
  prove 
  the 
  identity 
  of 
  the 
  group 
  A 
  of 
  the 
  various 
  sections, 
  

   whether 
  in 
  its 
  highly 
  altered 
  and 
  apparently 
  non-fossiliferous 
  state 
  

   or 
  in 
  its 
  less 
  altered 
  and 
  fossiliferous 
  condition. 
  Ascending 
  we 
  find 
  

  

  