﻿1864.] 
  BIGSBY 
  MISSING 
  SELIMENTAKY 
  FORMATIONS. 
  219 
  

  

  8. 
  With 
  a 
  Devonian 
  Roof. 
  — 
  Prof. 
  James 
  Hall 
  remarks 
  * 
  that 
  the 
  

   Chemung 
  group 
  of 
  North 
  America 
  affords 
  distinct 
  evidence 
  of 
  its 
  

   having 
  been 
  subaerial 
  from 
  time 
  to 
  time 
  : 
  in 
  its 
  ripple-marks, 
  its 
  ever- 
  

   changing 
  laminations, 
  in 
  the 
  increasing 
  quantity 
  of 
  its 
  Plants, 
  some 
  

   being 
  terrestrial 
  and 
  others 
  marine, 
  all 
  of 
  which 
  facts 
  bespeak 
  the 
  

   immediate 
  proximity 
  of 
  land. 
  There 
  are 
  in 
  the 
  Ithaca 
  subdivision 
  

   long 
  but 
  somewhat 
  indistinct 
  traces 
  of 
  lanceolate 
  and 
  falciform 
  

   Plants 
  ; 
  some 
  are 
  waifs, 
  and 
  others 
  are 
  natives. 
  It 
  is 
  at 
  Cooper's 
  

   Town, 
  on 
  the 
  eastern 
  edge 
  of 
  the 
  Hamilton 
  Sea, 
  where 
  the 
  earliest 
  

   remains 
  of 
  terrestrial 
  Plants 
  have 
  been 
  found. 
  

  

  The 
  Oriskany 
  Sandstone 
  (a 
  Lower 
  Devonian 
  bed), 
  thick 
  in 
  New 
  

   York 
  and 
  Pennsylvania, 
  almost 
  entirely 
  disappears, 
  together 
  with 
  

   other 
  members 
  of 
  this 
  system, 
  about 
  the 
  Upper 
  Mississippi. 
  

  

  On 
  the 
  river 
  just 
  named, 
  the 
  Portage 
  and 
  Chemung 
  groups, 
  at 
  the 
  

   top 
  of 
  the 
  Mid-Devonian, 
  lie 
  directly 
  on 
  the 
  Hamilton 
  Shales, 
  and 
  so 
  

   create 
  a 
  gap. 
  Here 
  also 
  we 
  might 
  expect 
  the 
  Cattskill 
  Mountain 
  

   group 
  (Old 
  Red 
  Sandstone, 
  or 
  Formations 
  IX. 
  X. 
  XI. 
  of 
  the 
  Penn- 
  

   sylvanian 
  Survey) 
  ; 
  but 
  its 
  place 
  is 
  occupied 
  by 
  great 
  masses 
  of 
  

   Lower 
  Carboniferous 
  limestones, 
  full 
  of 
  typical 
  fossils, 
  and 
  covering 
  

   Chemung 
  rocks, 
  a 
  deep-sea 
  condition 
  having 
  suddenly 
  supervened. 
  

  

  In 
  St. 
  Louis 
  County 
  (Missouri), 
  Chemung 
  rocks 
  repose 
  directly 
  on 
  

   Trenton 
  Limestone 
  f, 
  the 
  great 
  deposits 
  between 
  them 
  having 
  no 
  

   representative 
  there. 
  In 
  the 
  Report 
  quoted 
  below, 
  Dr. 
  Shumard 
  % 
  

   mentions 
  a 
  similar 
  fact 
  as 
  occurring 
  on 
  Grassy 
  River, 
  in 
  Rail's 
  and 
  

   Pike 
  Counties, 
  Missouri. 
  

  

  At 
  Marston's 
  Bridge, 
  on 
  the 
  River 
  Lamine 
  (Missouri), 
  the 
  Devonian 
  

   formation 
  rests 
  on 
  Calciferous 
  Sandstone 
  (Primordial). 
  Prof. 
  Swal- 
  

   low 
  gives 
  a 
  useful 
  table, 
  in 
  which 
  we 
  see 
  that 
  many 
  and 
  extensive 
  

   blanks 
  occur 
  in 
  these 
  highly 
  interesting 
  countries. 
  In 
  the 
  centre 
  

   of 
  the 
  State 
  of 
  Tennessee 
  §, 
  according 
  to 
  Mr. 
  J. 
  M. 
  Safford, 
  there 
  is 
  an 
  

   area, 
  about 
  eighty 
  miles 
  in 
  diameter, 
  which 
  was 
  probably 
  raised 
  above 
  

   the 
  ocean 
  by 
  the 
  disturbances 
  at 
  the 
  end 
  of 
  the 
  Lower 
  Silurian 
  

   period. 
  Here 
  an 
  Upper 
  Devonian 
  Shale 
  overlies 
  Lower 
  Silurian 
  ; 
  

   both 
  Upper 
  Silurian 
  and 
  Lower 
  Devonian 
  being 
  absent. 
  

  

  These 
  same 
  blanks 
  or 
  gaps 
  are 
  plentiful 
  in 
  Europe. 
  The 
  follow- 
  

   ing 
  are 
  a 
  few 
  examples. 
  As 
  in 
  America, 
  so 
  in 
  Russia 
  || 
  (at 
  Czarskoe- 
  

   celo) 
  sandy 
  and 
  marly 
  Devonian 
  beds 
  are 
  conformably 
  placed 
  over 
  

   Lower 
  Silurian 
  (Pleta 
  Limestone), 
  the 
  Devonian 
  rocks 
  being 
  loaded 
  

   with 
  Ichthyolites, 
  and 
  the 
  Silurian 
  with 
  Orthoceratites, 
  <fec. 
  In 
  the 
  

   middle 
  of 
  the 
  Cantabrian 
  Mountains^ 
  (Province 
  of 
  Leon, 
  Spain) 
  

   and 
  on 
  their 
  south 
  flank 
  are 
  two 
  bands 
  of 
  red 
  limestone 
  containing 
  

   fossils 
  indisputably 
  Primordial. 
  These 
  two 
  bands 
  are 
  at 
  least 
  

   seventy-five 
  miles 
  long 
  **, 
  and 
  are 
  vertical. 
  They 
  are 
  enclosed 
  con- 
  

   formably 
  within 
  massive 
  beds 
  of 
  Devonian 
  Sandstone. 
  In 
  this 
  in- 
  

  

  * 
  Palaeontology 
  of 
  New 
  York, 
  vol. 
  iii. 
  

   t 
  Shumard, 
  ' 
  Geol. 
  Surv. 
  Missouri,' 
  p. 
  184. 
  

  

  % 
  Geol. 
  Surv. 
  Missouri, 
  p. 
  123. 
  § 
  Dana's 
  ' 
  Manual,' 
  p. 
  228. 
  

  

  || 
  Murehison, 
  &c., 
  ' 
  Geol. 
  of 
  Russia,' 
  vol. 
  i. 
  p. 
  31. 
  

  

  *j[ 
  Casiano 
  de 
  Prado, 
  Bull. 
  Soc. 
  Geol. 
  France, 
  2 
  e 
  serie, 
  vol. 
  xvii. 
  p. 
  517. 
  

   ** 
  Casiano 
  de 
  Prado 
  and 
  Barrande, 
  Bull. 
  Soc. 
  Geol. 
  France, 
  2 
  e 
  serie. 
  vol. 
  xvi. 
  

   -passim, 
  and 
  vol. 
  xvii. 
  p. 
  789. 
  

  

  