﻿514 
  PROP. 
  E. 
  SCHMIDT 
  ON 
  THE 
  SILURIAN 
  STEATA 
  

  

  48. 
  On 
  the 
  Silurian 
  {and 
  Cambrian) 
  Strata 
  of 
  the 
  Baltic 
  Pro- 
  

   vinces 
  of 
  Russia, 
  as 
  compared 
  ivith 
  those 
  of 
  Scandinavia 
  and 
  

   the 
  British 
  Isles. 
  By 
  Professor 
  P. 
  Schmidt, 
  St. 
  Petersburg, 
  

   (Read 
  June 
  21, 
  1882.) 
  Communicated 
  by 
  Dr. 
  Henry 
  Wood- 
  

   ward, 
  P.R.S., 
  F.G.S. 
  

  

  [Plate 
  XXIIL] 
  

  

  Introduction. 
  

  

  I 
  have 
  recently 
  completed 
  the 
  first 
  part 
  of 
  a 
  memoir 
  upon 
  the 
  Silu- 
  

   rian 
  Trilobites 
  of 
  the 
  Baltic 
  provinces 
  of 
  Russia 
  *, 
  containing 
  a 
  

   special 
  geological 
  introduction. 
  This 
  work 
  is 
  already 
  in 
  the 
  

   hands 
  of 
  Silurian 
  geologists. 
  But 
  as 
  the 
  subject 
  of 
  my 
  memoir, 
  

   and 
  more 
  particularly 
  its 
  geological 
  introduction, 
  may 
  be 
  of 
  interest 
  

   to 
  British 
  geologists 
  in 
  general, 
  I 
  will 
  here 
  endeavour 
  to 
  

   develop 
  in 
  English 
  the 
  most 
  important 
  results 
  of 
  my 
  investigations, 
  

   pointing 
  out 
  at 
  the 
  same 
  time 
  more 
  especially 
  some 
  difficulties 
  and 
  

   controverted 
  points 
  in 
  the 
  parallelization 
  of 
  our 
  Silurian 
  strata 
  with 
  

   those 
  of 
  Scandinavia 
  and 
  the 
  British 
  Islands. 
  There 
  is 
  no 
  map 
  ac- 
  

   companying 
  my 
  memoir 
  ; 
  and 
  the 
  reader 
  is 
  therein 
  requested 
  to 
  refer 
  

   to 
  the 
  geological 
  map 
  of 
  the 
  Baltic 
  provinces 
  of 
  Russia, 
  published 
  at 
  

   Dorpat 
  in 
  1878 
  by 
  Prof. 
  Grewingk. 
  In 
  this 
  map 
  the 
  Silurian 
  part 
  

   was 
  drawn 
  by 
  myself. 
  The 
  accompanying 
  sketch 
  (PL 
  XXIII. 
  fig. 
  1). 
  

   will 
  serve 
  the 
  purpose 
  of 
  the 
  present 
  paper. 
  

  

  General 
  Characteristics. 
  

  

  The 
  whole 
  of 
  our 
  so-called 
  Eastern 
  Baltic 
  Silurian 
  spreads 
  over 
  a 
  

   large 
  area, 
  of 
  an 
  average 
  length 
  of 
  400 
  English 
  miles 
  and 
  a 
  breadth 
  

   of 
  80 
  miles, 
  through 
  the 
  provinces 
  of 
  Ingermanland 
  (St. 
  Petersburg), 
  

   Esthonia, 
  Livonia, 
  and 
  the 
  island 
  of 
  Oesel. 
  It 
  forms 
  one 
  complete 
  

   series 
  of 
  conformably 
  arranged 
  strata. 
  This 
  series 
  is 
  entirely 
  inde- 
  

   pendent 
  of 
  the 
  Devonian, 
  which 
  covers 
  the 
  Lower 
  Silurian 
  in 
  the 
  east, 
  

   and 
  the 
  Upper 
  Silurian 
  in 
  the 
  west, 
  without 
  showing 
  any 
  connecting 
  

   intermediate 
  links. 
  The 
  surface 
  of 
  the 
  country 
  occupied 
  by 
  our 
  

   system 
  forms 
  a 
  nearly 
  uniform 
  plain 
  (in 
  some 
  parts 
  of 
  the 
  country 
  

   scattered 
  over 
  with 
  narrow 
  ridges 
  or 
  asar 
  of 
  glacial 
  origin). 
  It 
  is 
  

   slightly 
  inclined 
  S. 
  and 
  S.W., 
  and 
  broken 
  abruptly 
  off 
  at 
  its 
  northern 
  

   border, 
  in 
  cliffs 
  from 
  50 
  to 
  150 
  feet 
  high 
  (the 
  so-called 
  "Glint 
  " 
  along 
  

   the 
  southern 
  coast 
  of 
  the 
  Gulf 
  of 
  Finland 
  ; 
  see 
  the 
  woodcut 
  in 
  Mur- 
  

   chison's 
  ' 
  Siluria, 
  ' 
  1867, 
  p. 
  356, 
  and 
  our 
  section, 
  PI. 
  XXIIL 
  fig. 
  3). 
  

   The 
  lowest 
  stages 
  are 
  visible 
  only 
  in 
  these 
  northern 
  cliffs 
  and 
  in 
  river- 
  

   sections 
  near 
  the 
  northern 
  border 
  of 
  our 
  system 
  ; 
  the 
  others 
  appear 
  as 
  

   low 
  terraces 
  in 
  the 
  interior 
  of 
  the 
  country, 
  and 
  are 
  represented 
  on 
  

  

  * 
  " 
  Eevision 
  der 
  ost-baltisclien 
  silurischen 
  Trilobiten, 
  nebst 
  geognostischer 
  

   Uebersicht 
  des 
  ost-baltischen 
  Silurgebietes, 
  von 
  F. 
  Schmidt. 
  Abtbeilung 
  1, 
  Phaco- 
  

   piden, 
  Cheiruriden, 
  und 
  Encrinuriden, 
  mit 
  16 
  Tafeln," 
  Memoires 
  de 
  l'Aca- 
  

   demie 
  Imperial 
  e 
  des 
  Sciences 
  de 
  St. 
  Petersbourg, 
  7 
  me 
  serie, 
  tome 
  xxx. 
  no. 
  1. 
  

   St. 
  Petersbourg, 
  1881. 
  

  

  