﻿606 
  PKOF. 
  C. 
  LAPWOETR 
  ON 
  THE 
  GIRVAN 
  SUCCESSION. 
  

  

  those 
  of 
  the 
  basal 
  zone. 
  Its 
  beds 
  are 
  much 
  distorted 
  and 
  shattered 
  ; 
  

   but 
  Graptolites 
  occur 
  in 
  the 
  carbonaceous 
  seams, 
  chiefly 
  — 
  

  

  Dicellograptus 
  Morrisi, 
  Hopk. 
  Olimacograptus 
  bicornis, 
  Hall. 
  

  

  Diplograptus 
  rugosus, 
  Emm. 
  

  

  Cascade-Beds 
  (Ba 
  4). 
  — 
  At 
  each 
  of 
  the 
  two 
  fine 
  waterfalls 
  above 
  

   mentioned 
  a 
  mass 
  of 
  coarse 
  green 
  grits 
  makes 
  its 
  appearance. 
  In 
  

   mineralogical 
  aspect 
  the}- 
  are 
  almost 
  identical 
  with 
  those 
  at 
  the 
  

   summit 
  of 
  the 
  Balclatchie 
  zone 
  of 
  the 
  Benan-conglomeratic 
  series, 
  as 
  

   displayed 
  in 
  the 
  Doon 
  Hill, 
  Daldowie, 
  and 
  elsewhere* 
  They 
  occa- 
  

   sionally 
  become 
  conglomeratic, 
  being 
  filled 
  with 
  zones 
  and 
  layers 
  of 
  

   small 
  boulders 
  of 
  greywacke 
  and 
  quartz. 
  They 
  include 
  between 
  

   them 
  a 
  series 
  of 
  dark 
  shales 
  and 
  mudstones, 
  striped 
  with 
  lines 
  of 
  

   carbonaceous 
  matter, 
  and 
  containing 
  frequent 
  bands 
  and 
  nodules 
  of 
  

   cement-stone. 
  These 
  calcareous 
  seams, 
  however, 
  unlike 
  those 
  of 
  the 
  

   succeeding 
  Whitehouse 
  Beds, 
  afford 
  no 
  examples 
  of 
  Brachiopoda, 
  but 
  

   are 
  crowded 
  with 
  Graptolites 
  in 
  excellent 
  preservation. 
  In 
  mine- 
  

   ralogical 
  aspect 
  the 
  beds 
  remind 
  us 
  of 
  those 
  found 
  on 
  both 
  margins 
  

   of 
  Ardwell 
  Bay, 
  at 
  the 
  summit 
  of 
  the 
  Ardwell 
  group 
  ; 
  and 
  their 
  

   identity 
  is 
  placed 
  beyond 
  question 
  by 
  the 
  fact 
  that 
  they 
  contain 
  all 
  

   the 
  peculiar 
  fossils 
  of 
  that 
  especial 
  locality, 
  viz. 
  : 
  — 
  

  

  Dicellograptus 
  Forckhammeri, 
  Gein. 
  

   Lasiograptus 
  rnargaritatus, 
  Lapw. 
  

   Diplograptus 
  pristis, 
  His. 
  

  

  Diplograptus 
  foliaeeus, 
  Murch. 
  

   Olimacograptus 
  caudatus, 
  Lapw. 
  

   Dicranograptus 
  ramosus, 
  Hall. 
  

  

  (2) 
  Bb. 
  Whitehouse 
  Beds. 
  — 
  Immediately 
  we 
  examine 
  the 
  floor 
  

   of 
  the 
  glen 
  below 
  the 
  second 
  waterfall, 
  it 
  becomes 
  evident 
  that 
  we 
  

   have 
  overpassed 
  the 
  limits 
  of 
  the 
  Ardwell 
  beds, 
  and 
  have 
  reached 
  

   the 
  more 
  varied 
  overlying 
  strata 
  of 
  Whitehouse 
  Bay. 
  The 
  beds 
  are 
  

   faulted 
  and 
  folded 
  even 
  more 
  intensely 
  than 
  upon 
  our 
  coast-section, 
  

   the 
  same 
  strata 
  coming 
  to 
  the 
  surface 
  again 
  and 
  again 
  as 
  we 
  descend 
  

   the 
  course 
  of 
  the 
  stream. 
  Prom 
  the 
  lower 
  cascade 
  to 
  the 
  point 
  

   in 
  the 
  glen 
  where 
  we 
  meet 
  with 
  the 
  terminal 
  calcareous 
  and 
  varie- 
  

   gated 
  beds 
  of 
  this 
  division, 
  the 
  distance, 
  as 
  measured 
  upon 
  these 
  

   strata 
  in 
  the 
  gorge 
  itself, 
  cannot 
  be 
  less 
  than 
  half 
  a 
  mile 
  ; 
  yet, 
  owing 
  

   to 
  the 
  many 
  repetitions 
  and 
  faults 
  that 
  have 
  affected 
  the 
  strata, 
  it 
  

   is 
  doubtful 
  if 
  their 
  collective 
  thickness 
  is 
  more 
  than 
  equal 
  to 
  that 
  

   estimated 
  in 
  our 
  typical 
  locality 
  upon 
  the 
  shore-line. 
  All 
  the 
  beds 
  

   have 
  a 
  southward 
  inclination, 
  as 
  if 
  passing 
  below 
  the 
  Cascade-grits 
  ; 
  

   but 
  when 
  the 
  several 
  recognizable 
  zones 
  are 
  studied 
  in 
  detail, 
  it 
  

   becomes 
  clearly 
  evident 
  that 
  they 
  are 
  arranged 
  in 
  series 
  of 
  zigzag 
  

   forms 
  upon 
  the 
  ground, 
  demonstrative 
  of 
  the 
  presence 
  of 
  numerous 
  

   broken 
  and 
  inverted 
  arches, 
  the 
  axes 
  of 
  which 
  cross 
  the 
  stream- 
  

   course 
  at 
  a 
  very 
  acute 
  angle. 
  Thus, 
  in 
  spite 
  of 
  the 
  prevalent 
  south- 
  

   ward 
  dip, 
  it 
  may 
  be 
  regarded 
  as 
  certain 
  that 
  there 
  is 
  a 
  general 
  

   ascending 
  sequence 
  as 
  we 
  descend 
  the 
  stream. 
  This 
  conclusion 
  is 
  

   supported 
  not 
  only 
  by 
  the 
  facts 
  obtainable 
  in 
  the 
  neighbouring 
  

   areas, 
  but 
  by 
  the 
  circumstance 
  that 
  the 
  variegated 
  seams 
  of 
  the 
  

   Upper 
  Whitehouse 
  Beds 
  are 
  found 
  at 
  the 
  north 
  end 
  of 
  the 
  section, 
  

   in 
  a 
  position 
  answering 
  to 
  their 
  place 
  in 
  the 
  sequence 
  of 
  the 
  corre- 
  

   sponding 
  strata 
  upon 
  the 
  shore-line. 
  

  

  