﻿1864] 
  

  

  HONETMAN 
  ARISAIG, 
  NOVA 
  SCOTIA. 
  

  

  343 
  

  

  order 
  of 
  the 
  strata. 
  The 
  undoubted 
  group 
  D, 
  or 
  the 
  approximate 
  

   equivalent 
  of 
  the 
  Upper 
  Ludlow, 
  is 
  distinguished 
  by 
  its 
  beautiful 
  

   and 
  variegated 
  stratification, 
  the 
  prevalent 
  colours 
  being 
  red, 
  grey, 
  

   and 
  green. 
  The 
  strata 
  are 
  inclined 
  40° 
  S.W., 
  except 
  where 
  the 
  

   strike 
  becomes 
  east 
  and 
  west. 
  This 
  is 
  the 
  case 
  with 
  the 
  uppermost 
  

   strata, 
  which 
  have 
  been 
  thrown 
  in 
  this 
  direction 
  by 
  the 
  amygdaloid 
  

   trap, 
  by 
  which 
  it 
  is 
  partly 
  overlain. 
  Here 
  our 
  Silurian 
  fauna 
  has 
  

   attained 
  its 
  greatest 
  development 
  as 
  regards 
  genera, 
  species, 
  and 
  

   individuals. 
  The 
  fossils 
  are 
  not, 
  however, 
  so 
  well 
  preserved 
  as 
  in 
  

   other 
  parts 
  of 
  the 
  series. 
  Of 
  the 
  class 
  Cephalopoda, 
  individuals 
  have 
  

   diminished 
  in 
  size, 
  while 
  it 
  has 
  received 
  many 
  accessions 
  in 
  genera 
  

   and 
  species. 
  Heteropoda, 
  Pteropoda, 
  and 
  Gasteropoda 
  abound, 
  the 
  

   Gasteropoda 
  being 
  generally 
  of 
  smaller 
  size 
  than 
  they 
  are 
  in 
  the 
  

   group 
  C. 
  Lamellibrancliiata 
  occur 
  in 
  greater 
  numbers 
  than 
  before, 
  

   especially 
  species 
  of 
  Clidophorus. 
  Brachiopoda 
  are 
  now 
  generally 
  

   of 
  smaller 
  species. 
  Crustacea 
  are 
  more 
  numerous, 
  both 
  in 
  genera 
  

   and 
  species, 
  and 
  Homalonotus 
  and 
  Calymene 
  are 
  of 
  rather 
  unusual 
  

   size. 
  One 
  pygidium 
  of 
  Homalonotus 
  Dawsoni, 
  Hall, 
  must 
  have 
  

   belonged 
  to 
  an 
  individual 
  six 
  or 
  seven 
  inches 
  in 
  length. 
  An 
  entire 
  

   Calymene 
  is 
  four 
  inches 
  in 
  length, 
  and 
  a 
  glabella 
  of 
  another 
  indi- 
  

   vidual 
  indicates 
  still 
  larger 
  proportions. 
  Entomostraca 
  appear 
  here 
  

   for 
  the 
  first 
  time, 
  and 
  in 
  considerable 
  variety 
  and 
  numbers, 
  near 
  the 
  

   top 
  of 
  the 
  series. 
  In 
  the 
  earlier 
  members 
  of 
  the 
  series 
  the 
  organisms 
  

   were 
  generally 
  insulated 
  ; 
  sometimes 
  they 
  occurred 
  in 
  small 
  groups, 
  

   and 
  in 
  thin 
  and 
  small 
  beds 
  of 
  limestone 
  ; 
  here 
  they 
  often 
  form 
  lime- 
  

   stone-bands 
  five 
  or 
  six 
  inches 
  in 
  thickness, 
  which 
  appear 
  to 
  have 
  

   been, 
  to 
  a 
  considerable 
  extent, 
  formed 
  of 
  the 
  debris 
  of 
  organisms. 
  

   In 
  this 
  member 
  of 
  the 
  series 
  the 
  fossils 
  are 
  generally 
  fragmentary, 
  

   entire 
  specimens 
  being 
  very 
  seldom 
  found. 
  The 
  following 
  list 
  shows 
  

   the 
  character 
  of 
  the 
  fauna 
  of 
  the 
  group 
  D 
  : 
  — 
  

  

  Clidophorus 
  evectus, 
  Hall. 
  

   Clidophorus 
  elongatus, 
  Hall. 
  

   Clidophorus 
  seniiradiatus, 
  Hall. 
  

   Clidophorus 
  nuculiforrnis, 
  Hall. 
  

   Clidophorus 
  subovatus, 
  Hall. 
  

   Avicula 
  Honeyrnani, 
  Hall. 
  

   Pterinea 
  retroflexa. 
  

   Orthonota 
  (like 
  many 
  Ludlow 
  species, 
  

  

  Salter). 
  

   Goniophora 
  cymbgeforinis, 
  Sow. 
  

   Chonetes 
  Nova-Scotica, 
  Hall. 
  

   Chonetes 
  tenuistriata, 
  Hall. 
  

   Orthis, 
  2 
  sp. 
  

  

  Spirifer 
  subsulcatus, 
  Hall. 
  

   Rhynchonella, 
  3 
  sp. 
  

   Discina 
  rugata, 
  Sow. 
  

   Discina? 
  lineata. 
  

   Discina? 
  tenuilamellata, 
  Hall. 
  

   Crania 
  Acadiensis, 
  Hall. 
  

   Lingula, 
  sp. 
  

  

  Homalonotus 
  Dawsoni, 
  Hall. 
  

   Homalonotus 
  Knightii, 
  Konig. 
  

   Dalmania 
  Logani, 
  Hall. 
  

   Phacops 
  Downingia?, 
  Salt. 
  

  

  Lituites. 
  

  

  Phragmoceras. 
  

  

  Ormoceras 
  ? 
  

  

  ? 
  long, 
  tapering, 
  and 
  recurved. 
  

  

  Orthoceras 
  nummulare, 
  Sow. 
  

  

  Orthoceras, 
  very 
  like 
  0. 
  buttutum, 
  

  

  Sow. 
  

   Orthoceras 
  ibex, 
  Sow. 
  

   Orthoceras 
  exornatum, 
  Dawson. 
  

   Orthoceras 
  punctostriatum, 
  Hall. 
  

   Orthoceras, 
  4 
  sp. 
  

   Bellerophon 
  trilobatus, 
  Sow. 
  

   Bellerophon 
  carinatus. 
  Sow. 
  

   Bellerophon 
  striatus, 
  D 
  Orb. 
  

   Bellerophon 
  expansus, 
  Sow. 
  

   Theca 
  Forbesii, 
  Sharype. 
  

   Coleoprion?, 
  sp. 
  

   Murchisonia 
  Arisaigensis, 
  Hull. 
  

   Murchisonia 
  aciculata, 
  Hall. 
  

   Pleurotomaria. 
  

  

  Modiolopsis 
  ? 
  rhomboidea, 
  Hall. 
  

   Modiolopsis 
  subnasuta, 
  Hall. 
  

   Clidophorus 
  cuncatus, 
  Hall. 
  

   Clidophorus 
  concentricus, 
  Hall. 
  

  

  