﻿"^°L 
  53-] 
  FOSSILS 
  FROM 
  THE 
  MORTE 
  SLATES, 
  ETC. 
  445* 
  

  

  VI. 
  Description 
  op 
  the 
  Fossils. 
  

   By 
  the 
  Rev. 
  G. 
  F. 
  Whibborbte, 
  M.A., 
  F.G.S. 
  

  

  Dalmaxites 
  (Cryphjees) 
  laciniattts, 
  F. 
  Rbmer, 
  ? 
  var. 
  occi- 
  

   dexNtalis. 
  (PI. 
  XXXIII. 
  figs. 
  9-13.) 
  

  

  Locality. 
  Oakhampton 
  Quarry. 
  Four 
  heads, 
  5 
  tails. 
  

  

  Size, 
  Head 
  about 
  15 
  mm. 
  loug, 
  32 
  mm. 
  wide. 
  Tail 
  about 
  

   15 
  mm. 
  long, 
  17 
  mm. 
  wide. 
  Tail-spines 
  nearly 
  10 
  mm. 
  long. 
  

  

  Description. 
  Head 
  wide, 
  semi-oval, 
  slightly 
  lobate 
  in 
  front. 
  

   Glabella 
  large, 
  subconical, 
  with 
  large, 
  tuberculate, 
  overhanging 
  

   anterior 
  lobe, 
  and 
  with 
  three 
  lateral 
  lobes, 
  of 
  which 
  the 
  two 
  

   upper 
  are 
  rather 
  large 
  and 
  subtriangular, 
  and 
  the 
  lower 
  is 
  small 
  and 
  

   narrow 
  ; 
  furrows 
  strong, 
  nearly 
  reaching 
  to 
  the 
  centre. 
  Eyes 
  about 
  

   \ 
  the 
  length 
  of 
  the 
  head, 
  prominent, 
  composed 
  of 
  more 
  than 
  170 
  

   lenses 
  in 
  about 
  28 
  vertical 
  rows 
  of 
  9 
  or 
  fewer 
  lenses 
  each. 
  Cheek- 
  

   spines 
  long, 
  narrow, 
  curved, 
  tapering. 
  Neck-lobe 
  prominent. 
  ' 
  

  

  Pygidium 
  elongate, 
  rather 
  narrow, 
  subtriangular, 
  with 
  a 
  rather 
  

   narrow 
  tapering 
  axis 
  of 
  probably 
  about 
  12 
  segments 
  ; 
  lateral 
  lobes 
  

   with 
  5 
  strongly 
  marked 
  widening 
  ribs, 
  indistinctly 
  bordered, 
  and 
  

   bearing 
  5 
  very 
  long, 
  narrow, 
  distant, 
  thorn-like, 
  nearly 
  straight 
  

   lateral 
  spines, 
  and 
  a 
  (seemingly) 
  rather 
  shorter 
  and 
  broader 
  terminal 
  

   spine. 
  

  

  Remarks. 
  Salter 
  1 
  refers 
  to 
  C. 
  punctatus, 
  Steininger, 
  2 
  three 
  

   specimens 
  from 
  Liskeard, 
  which 
  chiefly 
  differ 
  from 
  ours 
  in 
  having 
  

   smaller 
  eyes, 
  longer 
  and 
  stouter 
  cheek-spines, 
  and 
  a 
  broader 
  tail. 
  

   Kayser, 
  3 
  however, 
  tabulates 
  the 
  species 
  of 
  CrypJiceus 
  in 
  two 
  

   divisions, 
  based 
  on 
  the 
  presence 
  or 
  absence 
  of 
  a 
  clear 
  terminal 
  spine. 
  

   Such 
  a 
  spine, 
  according 
  to 
  him 
  and 
  other 
  authors, 
  is 
  wanting 
  in 
  

   O. 
  punctatus 
  ; 
  but 
  our 
  specimens 
  always 
  have 
  clear 
  indications 
  of 
  

  

  France, 
  however, 
  so 
  soon 
  as 
  we 
  come 
  to 
  the 
  horizon 
  of 
  the 
  Orthis 
  Mormieri- 
  

   sandstone, 
  Cryphaus 
  is' 
  abundant, 
  as 
  also 
  in 
  the 
  0. 
  undata-beds, 
  while 
  it 
  

   becomes 
  scarcer 
  in 
  the 
  Sp. 
  Deche?ii-beds 
  ( 
  = 
  Erbray 
  Limestone), 
  and 
  in 
  the 
  

   Phacops 
  Potieri-zone 
  ( 
  = 
  Grauwacke 
  of 
  Hierges). 
  Again, 
  in 
  the 
  Devonian 
  of 
  

   Spain 
  and 
  in 
  that 
  of 
  the 
  Bosphorus, 
  the 
  genus 
  Cryplmus 
  is 
  found 
  to 
  occur. 
  

  

  ' 
  In 
  America, 
  the 
  genus 
  Dalmanites 
  passes 
  up, 
  with 
  but 
  little 
  modification, 
  

   from 
  the 
  Silurian 
  into 
  the 
  Devonian 
  ; 
  but, 
  so 
  soon 
  as 
  we 
  reach 
  the 
  base 
  of 
  the 
  

   Coblentzian 
  (Oriskany), 
  types 
  appear 
  in 
  conjunction 
  with 
  it 
  which 
  are 
  referred 
  

   to 
  it 
  under 
  the 
  heading 
  of 
  subgenera, 
  and 
  are 
  evidently 
  derived 
  from 
  it. 
  

   Among 
  these, 
  Cryphcsus 
  is 
  the 
  latest 
  comer, 
  and 
  is 
  the 
  one 
  which 
  persists 
  the 
  

   longest 
  (up 
  to 
  the 
  top 
  of 
  the 
  Coblentzian). 
  It 
  attains 
  its 
  greatest 
  development 
  

   in 
  the 
  Hamilton 
  Group, 
  especially 
  at 
  the 
  horizon 
  of 
  the 
  Hamilton 
  Shales, 
  where 
  

   the 
  other 
  subgenera 
  of 
  Dalmanites 
  cease 
  to 
  appear, 
  and 
  where 
  this 
  genus 
  itself 
  

   is 
  merely 
  represented 
  by 
  a 
  single 
  species. 
  Finally, 
  a 
  last 
  survivor 
  of 
  the 
  group 
  

   recurs 
  in 
  the 
  Tully 
  Limestone, 
  that 
  is, 
  at 
  the 
  horizon 
  of 
  the 
  Givetian. 
  

  

  ' 
  From 
  the 
  foregoing 
  facts 
  we 
  conclude 
  that 
  Cn/phaits 
  is 
  more 
  especially 
  

   localized 
  in 
  the 
  Coblentzian 
  beds 
  of 
  the 
  Rhine 
  and 
  the 
  Harz, 
  and 
  also 
  in 
  those 
  

   of 
  the 
  West 
  of 
  France, 
  Spain, 
  and 
  the 
  Bosphorus 
  (the 
  last 
  three 
  are 
  very 
  similar 
  

   from 
  many 
  points 
  of 
  view), 
  while 
  in 
  America 
  it 
  made 
  its 
  appearance 
  later 
  and 
  

   did 
  not 
  so 
  soon 
  become 
  extinct.' 
  — 
  May 
  15th, 
  1897.] 
  

  

  1 
  1864. 
  Salter, 
  ■ 
  Mon. 
  Brit. 
  Trilob.,' 
  p. 
  59, 
  & 
  pi. 
  i. 
  figs. 
  17-19. 
  

  

  2 
  1834. 
  Steininger, 
  Mem. 
  Soc. 
  geol. 
  Fr. 
  vol. 
  i. 
  pt. 
  ii. 
  p. 
  356, 
  & 
  pi. 
  xxi. 
  figs. 
  7-76. 
  

  

  3 
  1878. 
  Kayser, 
  Abh. 
  geol. 
  Specialk. 
  Preuss. 
  vol. 
  ii. 
  pt. 
  iv. 
  p. 
  33. 
  

  

  