﻿530 
  FROF. 
  F. 
  SCHMIDT 
  ON 
  THE 
  SILURIAN 
  STRATA. 
  

  

  Our 
  stage 
  K 
  fully 
  corresponds 
  to 
  the 
  uppermost 
  stage 
  of 
  Gothland 
  

   (South 
  Gothland 
  according 
  to 
  Lindstrom 
  and 
  myself), 
  to 
  the 
  highest 
  

   Silurian 
  stage 
  in 
  Norway 
  (8 
  of 
  Ivjerulf), 
  and 
  to 
  the 
  Onondaga 
  salt- 
  

   group 
  and 
  the 
  Waterlime 
  group, 
  together 
  with 
  the 
  Tentaculite-iime- 
  

   stone 
  of 
  New 
  York. 
  

  

  Relation 
  of 
  Silurian 
  and 
  Devonian 
  Strata. 
  

  

  With 
  us, 
  as 
  in 
  Scandinavia 
  and 
  in 
  England, 
  the 
  Silurian 
  system 
  is 
  

   completed 
  by 
  our 
  stage 
  K 
  and 
  its 
  corresponding 
  strata 
  already 
  de- 
  

   scribed. 
  The 
  Helderberg 
  group 
  of 
  America, 
  as 
  well 
  as 
  the 
  stages 
  F, 
  

   G, 
  and 
  H 
  of 
  Barrande, 
  I 
  should 
  rather 
  prefer 
  to 
  call 
  Devonian, 
  in 
  ac- 
  

   cordance 
  with 
  the 
  views 
  of 
  Dr. 
  Kayser. 
  To 
  the 
  same 
  lowest 
  Devonian 
  

   may 
  belong 
  also 
  the 
  so-called 
  Upper 
  Silurian 
  of 
  the 
  Ural 
  and 
  Altai 
  

   Mountains, 
  with 
  ribbed 
  Pcntameri 
  and 
  several 
  Trilobites 
  and 
  Brachio- 
  

   poda, 
  reminding 
  us 
  of 
  analogous 
  forms 
  of 
  the 
  uppermost 
  Bohemian 
  

   stages. 
  In 
  England 
  as 
  well 
  as 
  in 
  Podolia 
  and 
  Gahcia 
  on 
  the 
  Dniester 
  

   the 
  uppermost 
  Silurians 
  pass 
  gradually 
  over 
  into 
  beds 
  containing 
  

   Cephalaspida, 
  Pteraspida, 
  and 
  some 
  new 
  Eurypterida. 
  It 
  is 
  difficult 
  

   to 
  decide 
  the 
  question 
  whether 
  these 
  Cephalasjris-beds 
  should 
  also 
  be 
  

   named 
  Devonian, 
  or 
  whether 
  it 
  would 
  be 
  more 
  convenient 
  to 
  unite 
  

   them 
  with 
  the 
  uppermost 
  Silurian, 
  in 
  which 
  the 
  above-named 
  groups 
  

   of 
  Cephalaspida, 
  Pteraspida, 
  and 
  Eurypterida 
  are 
  all 
  known 
  to 
  

   begin. 
  

  

  With 
  us, 
  in 
  the 
  Baltic 
  Provinces, 
  we 
  have 
  no 
  traces 
  of 
  the 
  above- 
  

   mentioned 
  passage-beds 
  or 
  the 
  lowest 
  Devonian. 
  The 
  Silurian 
  

   strata 
  are 
  covered 
  unconformably 
  by 
  the 
  Old 
  Eed 
  Sandstone, 
  with 
  

   Coccostevs, 
  Asterolejris, 
  Bothriolepis, 
  Homosteus, 
  and 
  Heterosteus. 
  The 
  

   Devonian 
  is 
  superposed 
  upon 
  the 
  Lowest 
  Silurian 
  (the 
  Orthoceratite- 
  

   limestone) 
  in 
  the 
  cast, 
  on 
  the 
  river 
  Sjas, 
  and 
  covers 
  . 
  the 
  younger 
  

   Silurian 
  strata 
  in 
  turn 
  as 
  we 
  advance 
  to 
  the 
  west. 
  Thus 
  at 
  Paw- 
  

   lawskit 
  covers 
  the 
  EchinosphaBrite-limestone 
  (C), 
  near 
  Gatschmathe 
  

   Jewe 
  stage 
  (D), 
  on 
  the 
  Narowa 
  the 
  Wesenberg 
  stage 
  (E), 
  and 
  in 
  the 
  

   west 
  of 
  Livonia, 
  at 
  Torgel, 
  near 
  Pernan, 
  the 
  stage 
  H 
  is 
  covered 
  by 
  

   Devonian 
  sandstones 
  with 
  fish-remains 
  and 
  the 
  curious 
  coaly 
  stems 
  of 
  

   the 
  still 
  problematical 
  Aulacophycus 
  striatus, 
  Eichw., 
  regarded 
  by 
  

   Eichwald 
  as 
  an 
  Alga, 
  but 
  having 
  a 
  coniferal 
  structure, 
  according 
  to 
  

   Goppert. 
  Our 
  Devonian 
  rocks 
  do 
  not 
  anywhere 
  cover 
  immediately 
  

   the 
  stage 
  K 
  ; 
  and 
  the 
  two 
  systems 
  must 
  be 
  regarded 
  as 
  entirely 
  in- 
  

   dependent 
  of 
  each 
  other 
  throughout 
  the 
  whole 
  extent 
  of 
  our 
  eastern 
  

   Baltic 
  territory 
  ; 
  while 
  the 
  three 
  divisions 
  of 
  the 
  Silurian 
  (according 
  

   to 
  Murchison 
  and 
  Barrande), 
  or 
  the 
  Cambrian 
  and 
  Silurian 
  of 
  

   others, 
  or 
  the 
  Cambrian, 
  Ordovician, 
  and 
  Silurian 
  of 
  Prof. 
  Lapworth, 
  

   form 
  one 
  regular 
  coherent 
  series 
  of 
  strata 
  apparently 
  deposited 
  in 
  

   one 
  and 
  the 
  same 
  ancient 
  ocean, 
  to 
  which 
  series, 
  so 
  far 
  as 
  our 
  country 
  

   is 
  concerned, 
  I 
  would 
  prefer 
  to 
  attribute 
  the 
  name 
  of 
  a 
  " 
  System." 
  

  

  The 
  Swedish 
  Silurian 
  strata 
  on 
  the 
  west 
  side 
  of 
  the 
  Baltic 
  corre- 
  

   spond 
  so 
  accurately 
  to 
  ours 
  on 
  the 
  east 
  side, 
  according 
  to 
  the 
  incli- 
  

   nation 
  of 
  strata 
  and 
  the 
  formation 
  of 
  the 
  sea-shore 
  cliff, 
  that 
  I 
  found 
  

   it 
  possible 
  to 
  reconstruct 
  a 
  section 
  through 
  the 
  Baltic, 
  from 
  Wiborg 
  

  

  

  