﻿PROCEEDINGS 
  OF 
  THE 
  GEOLOGICAL 
  SOCIETY. 
  5 
  

  

  years 
  since 
  pointed 
  out. 
  In 
  some 
  parts 
  of 
  North 
  America 
  he 
  found 
  

   the 
  Montalban 
  resting 
  unconformably 
  on 
  Laurentian. 
  Above 
  the 
  

   Montalban 
  comes 
  the 
  Taconian 
  (Lower 
  Taconic 
  of 
  Emmons), 
  a 
  

   series 
  of 
  quartzites 
  and 
  soft 
  micaceous 
  schists, 
  with 
  dolomites 
  and 
  

   marbles. 
  All 
  these 
  various 
  series 
  are 
  older 
  than 
  the 
  Lower 
  

   Cambrian 
  (Menevian) 
  strata 
  of 
  North 
  America; 
  and 
  it 
  may 
  be 
  

   added 
  that 
  the 
  Keweenian 
  or 
  great 
  copper-bearing 
  series 
  of 
  Lake 
  

   Superior 
  there 
  occupies 
  a 
  position 
  between 
  the 
  Montalban 
  and 
  the 
  

   Cambrian. 
  

  

  In 
  the 
  Alps 
  the 
  speaker 
  recognizes 
  the 
  Laurentian, 
  Huronian, 
  and 
  

   Montalban, 
  all 
  of 
  which 
  he 
  has 
  lately 
  seen 
  in 
  the 
  Biellese, 
  at 
  the 
  

   foot 
  of 
  Mount 
  Viso, 
  in 
  Piedmont. 
  The 
  Huronian 
  is 
  the 
  great 
  pietre 
  

   vercli 
  group 
  of 
  the 
  Italians 
  ; 
  and 
  much 
  of 
  what 
  has 
  been 
  called 
  

   altered 
  Trias 
  in 
  this 
  region 
  is, 
  in 
  his 
  opinion, 
  probably 
  Taconian. 
  

   The 
  Montalban 
  forms 
  the 
  southern 
  slope 
  of 
  Mont 
  St. 
  Gothard, 
  and 
  

   is 
  the 
  muscovite 
  gneiss 
  and 
  mica-schist 
  of 
  the 
  Saxon 
  Erzgebirge. 
  

   Here 
  Dr. 
  Credner 
  and 
  his 
  assistants 
  of 
  the 
  Geological 
  Survey 
  have 
  

   described 
  abundant 
  conglomerates 
  holding 
  pebbles 
  of 
  Laurentian 
  

   rocks 
  imbedded 
  in 
  the 
  Upper 
  or 
  Montalban 
  gneiss. 
  The 
  pre- 
  

   Cambrian 
  age 
  of 
  this 
  has 
  been 
  shown 
  by 
  Credner, 
  who 
  has 
  proved 
  

   by 
  careful 
  survey 
  that 
  the 
  so-called 
  younger 
  or 
  Palaeozoic 
  gneisses 
  of 
  

   Naumann 
  are 
  really 
  but 
  a 
  continuous 
  part 
  of 
  the 
  older 
  series. 
  Late 
  

   surveys 
  also 
  show 
  that 
  the 
  crystalline 
  rocks 
  of 
  the 
  Taunus 
  are 
  

   really 
  Eozoic 
  and 
  not, 
  as 
  formerly 
  maintained, 
  Devonian 
  in 
  age. 
  

  

  The 
  speaker 
  insisted 
  upon 
  the 
  fact 
  that 
  where 
  newer 
  strata 
  are 
  

   in 
  unconformable 
  contact 
  with 
  older 
  ones, 
  the 
  effect 
  of 
  lateral 
  move- 
  

   ments 
  of 
  compression, 
  involving 
  the 
  two 
  series, 
  is 
  generally 
  to 
  cause 
  

   the 
  newer 
  and 
  more 
  yielding 
  strata 
  to 
  dip 
  towards 
  and 
  even 
  beneath 
  

   the 
  edges 
  of 
  the 
  older 
  rock, 
  a 
  result 
  due 
  to 
  folds, 
  often 
  with 
  inver- 
  

   sion, 
  sometimes 
  passing 
  into 
  faults. 
  This 
  phenomenon 
  throws 
  much 
  

   light 
  on 
  the 
  supposed 
  recency 
  of 
  many 
  crystalline 
  schists. 
  

  

  The 
  following 
  communications 
  were 
  read 
  : 
  — 
  

  

  1. 
  " 
  Additional 
  Evidence 
  on 
  the 
  Land-Plants 
  from 
  the 
  Pen-y-glog 
  

   Slate-quarry, 
  near 
  Corwen." 
  By 
  Henry 
  Hicks, 
  Esq., 
  M.D., 
  F.G.S. 
  

  

  2. 
  " 
  Notes 
  on 
  Prototaxites 
  and 
  Pachytlieca 
  from 
  the 
  Denbighshire 
  

   Grits 
  of 
  Corwen, 
  North 
  "Wales." 
  By 
  Principal 
  Dawson, 
  LL.D., 
  

   F.B.S., 
  F.G.S. 
  

  

  The 
  following 
  specimens 
  were 
  exhibited 
  : 
  — 
  

  

  Land-plants 
  from 
  the 
  Pen-y-glog 
  Slate-quarry, 
  near 
  Corwen, 
  

   exhibited 
  by 
  Dr. 
  Hicks 
  in 
  illustration 
  of 
  his 
  paper. 
  

  

  A 
  specimen 
  of 
  Prototaxites 
  from 
  Bay 
  dc 
  Chaleurs, 
  and 
  specimens 
  

   of 
  Pachytlieca 
  from 
  llumney, 
  exhibited 
  by 
  W. 
  Carruthers, 
  Esq., 
  

   F.R.S., 
  F.G.S. 
  

  

  Two 
  sections 
  of 
  Pachytheca, 
  exhibited 
  by 
  W. 
  T. 
  Thiselton 
  Dyer, 
  

   Esq., 
  F.E.S. 
  

  

  