﻿1863.] 
  DUNCAN 
  WEST 
  INDIAN 
  CORALS. 
  41 
  

  

  The 
  MS. 
  of 
  Mr. 
  Lonsdale 
  contains 
  an 
  elaborate 
  examination 
  of 
  this 
  

   form, 
  but 
  the 
  above 
  specific 
  diagnosis 
  is 
  not 
  taken 
  from 
  that 
  source. 
  

   All 
  the 
  Pocilloporce 
  yet 
  described 
  are 
  from 
  the 
  Pacific, 
  East 
  Indian, 
  

   and 
  South 
  Sea 
  provinces, 
  and 
  Pocillopora 
  madreporacea, 
  from 
  the 
  

   Turin 
  and 
  Dax 
  Miocene, 
  is 
  the 
  only 
  fossil 
  form. 
  

  

  IY. 
  General 
  Observations. 
  

  

  It 
  is 
  very 
  remarkable 
  that 
  simple 
  Corals 
  should 
  predominate 
  in 
  

   San 
  Domingo, 
  whilst 
  there 
  are 
  no 
  instances 
  of 
  their 
  having 
  been 
  found 
  

   in 
  Antigua. 
  It 
  would 
  appear 
  that 
  something 
  like 
  this 
  distribution 
  

   exists 
  at 
  the 
  present 
  day, 
  for 
  simple 
  Corals 
  and 
  pedunculated 
  com- 
  

   pound 
  forms 
  are 
  very 
  common 
  around 
  the 
  northern 
  Antilles, 
  but 
  

   rare 
  in 
  the 
  eastern 
  Caribbean 
  Sea. 
  Rich 
  as 
  the 
  Chert 
  and 
  Marl 
  of 
  

   Antigua 
  are 
  in 
  Zoaniharia, 
  they 
  are 
  surpassed, 
  both 
  in 
  genera 
  and 
  

   species, 
  by 
  the 
  shales 
  and 
  limestones 
  of 
  San 
  Domingo. 
  The 
  extent 
  of 
  

   the 
  San-Domingan 
  Tertiarics 
  will 
  account, 
  in 
  some 
  degree, 
  for 
  their 
  

   comprehensive 
  Coral-fauna 
  ; 
  and 
  the 
  general 
  absence 
  of 
  the 
  siliceous 
  

   form 
  of 
  mineralization, 
  which 
  appears 
  to 
  be 
  quite 
  as 
  destructive 
  as 
  

   preservative 
  in 
  Antigua, 
  has 
  tended 
  to 
  the 
  transmission 
  of 
  fossils 
  

   in 
  great 
  perfection. 
  The 
  Nivaje 
  and 
  other 
  deposits 
  cover 
  an 
  extent 
  

   of 
  country 
  of 
  more 
  than 
  3000 
  square 
  miles, 
  and 
  they 
  are 
  simply 
  the 
  

   remains 
  of 
  a 
  long 
  and 
  broad 
  barrier-reef 
  with 
  its 
  detritus 
  and 
  deep- 
  

   sea 
  Coral-mud. 
  The 
  mountain-range 
  which 
  supported 
  the 
  reef 
  runs 
  

   east 
  and 
  west 
  for 
  about 
  100 
  miles, 
  at 
  a 
  distance 
  of 
  30 
  miles 
  from 
  the 
  

   sea, 
  and 
  the 
  intervening 
  area 
  is 
  filled 
  up 
  by 
  argillaceous 
  beds, 
  lime- 
  

   stones 
  called 
  tufaceous, 
  but 
  not 
  really 
  so, 
  and 
  a 
  deep-blue 
  sand}* 
  shale. 
  

   The 
  thickness 
  of 
  these 
  sedimentary 
  and 
  reef 
  deposits 
  must 
  be 
  very 
  

   great, 
  for 
  the 
  cliffs 
  through 
  which 
  the 
  rivers 
  rising 
  in 
  the 
  mountain- 
  

   range 
  have 
  cut 
  their 
  way 
  are 
  often 
  200 
  feet 
  high 
  close 
  to 
  the 
  sea, 
  whilst 
  

   the 
  altitude 
  of 
  San 
  Jago, 
  which 
  is 
  20 
  miles 
  inland, 
  is 
  2000 
  feet, 
  the 
  

   strata 
  dipping 
  gently 
  to 
  the 
  N.N.nV. 
  Remains 
  of 
  the 
  reef 
  exist 
  along 
  

   the 
  mountain-side, 
  and 
  the 
  sedimentary 
  beds 
  between 
  it 
  and 
  the 
  sea 
  

   contain 
  more 
  or 
  less 
  perfect 
  Corals, 
  Testacea, 
  Crustacean 
  remains, 
  

   Fish-teeth, 
  and 
  enormous 
  deposits 
  of 
  Foraminifera 
  and 
  Coral-de- 
  

   tritus 
  *. 
  

  

  The 
  discovery 
  of 
  a 
  Pocillopora 
  in 
  the 
  Nivaje 
  shale 
  is 
  one 
  of 
  the 
  

   many 
  proofs 
  of 
  a 
  former 
  connexion 
  between 
  the 
  East 
  and 
  West 
  Indian 
  

   Coral-faunae, 
  which 
  has 
  been 
  asserted 
  in 
  my 
  former 
  communication. 
  

   This 
  is 
  also 
  the 
  only 
  Tabulate 
  Coral 
  which 
  has 
  been 
  -found 
  in 
  the 
  

   San-Domingan 
  Miocene. 
  Found 
  with 
  Alveoporce, 
  it 
  proves 
  the 
  ex- 
  

   istence 
  of 
  a 
  surf-beaten 
  reef 
  in 
  the 
  Miocene 
  period 
  off 
  San 
  Domingo 
  ; 
  

   and, 
  taken 
  in 
  consideration 
  with 
  the 
  discovery 
  of 
  great 
  Astrasans 
  and 
  

   huge 
  simple 
  Corals, 
  it 
  indicates 
  a 
  great 
  luxuriance 
  of 
  Coral-growth 
  

   and 
  great 
  variation 
  in 
  sea-depth. 
  

  

  Including 
  the 
  forms 
  described 
  in 
  the 
  first 
  part 
  of 
  this 
  communica- 
  

   tion, 
  there 
  are 
  no 
  less 
  than 
  47 
  species 
  of 
  Corals 
  from 
  the 
  restricted 
  

  

  * 
  See 
  Mr. 
  Carrick 
  Moore 
  on 
  the 
  Tertiary 
  beds 
  of 
  San 
  Domingo, 
  Quart. 
  Journ. 
  

   Geol. 
  Soc. 
  vol. 
  yi. 
  p. 
  39. 
  

  

  