﻿Report 
  of 
  the 
  State 
  Geologist. 
  691 
  

  

  least, 
  they 
  have 
  so 
  much 
  the 
  appearance 
  of 
  metamorphosed 
  

   sediments 
  that 
  the 
  burden 
  of 
  proof 
  must 
  rest 
  with 
  those 
  who 
  

   would 
  maintain 
  for 
  them 
  a 
  different 
  origin. 
  

  

  While 
  the 
  summit 
  of 
  the 
  Oswegatchie 
  series 
  is 
  clearly 
  defined 
  

   by 
  a 
  great 
  unconformity, 
  the 
  position 
  of 
  its 
  base 
  is, 
  as 
  yet, 
  a 
  

   matter 
  of 
  doubt. 
  The 
  reasons 
  for 
  this 
  will 
  become 
  plain 
  upon 
  

   the 
  consideration 
  of 
  the 
  distribution 
  and 
  character 
  of 
  the 
  

   rocks, 
  and 
  their 
  structural 
  relations. 
  The 
  areal 
  distribution 
  

   of 
  gneiss 
  and 
  limestone 
  shown 
  on 
  the 
  map 
  and 
  the 
  steep 
  dips 
  

   common 
  in 
  the 
  rocks 
  suggest 
  the 
  possibility 
  of 
  the 
  existence 
  of 
  a 
  

   series 
  of 
  folds 
  with 
  crests 
  and 
  troughs 
  pitching 
  to 
  the 
  northeast. 
  

   As 
  nearly 
  all 
  the 
  recorded 
  dips 
  are 
  northerly 
  it 
  would 
  seem 
  

   that 
  there 
  may 
  be 
  an 
  overturning 
  of 
  the 
  folds, 
  giving 
  the 
  axes 
  

   (the 
  axial 
  planes 
  which 
  bisect 
  the 
  folds)* 
  an 
  inclination 
  to 
  the 
  

   northwest. 
  On 
  this 
  point, 
  however, 
  there 
  is 
  an 
  insufficiency 
  of 
  

   data; 
  although, 
  it 
  may 
  be 
  added, 
  the 
  character 
  of 
  the 
  minor 
  

   distortions 
  so 
  commonly 
  seen 
  in 
  the 
  black 
  schists 
  is 
  in 
  harmony 
  

   with 
  this 
  view. 
  This 
  hypothesis 
  of 
  folding 
  affords 
  the 
  most 
  

   satisfactory 
  explanation 
  of 
  the 
  peculiar 
  distribution 
  of 
  the 
  rocks 
  

   and 
  other 
  facts 
  now 
  at 
  hand 
  ; 
  and 
  while 
  areal 
  relations 
  supply 
  a 
  

   very 
  unsatisfactory 
  basis 
  for 
  structural 
  conclusions 
  in 
  the 
  present 
  

   instance, 
  more 
  reliable 
  data 
  failing 
  us, 
  a 
  provisional 
  acceptance 
  of 
  

   such 
  conclusions, 
  until 
  they 
  may 
  be 
  established 
  or 
  discredited 
  by 
  

   further 
  investigation, 
  will 
  aid, 
  rather 
  than 
  retard, 
  the 
  inquiry. 
  

  

  Assuming 
  for 
  the 
  present 
  this 
  interpretation 
  of 
  the 
  structure, 
  

   the 
  question 
  remains 
  : 
  Does 
  all 
  of 
  the 
  gneiss 
  which 
  spreads 
  over 
  

   so 
  much 
  of 
  the 
  region 
  belong 
  with 
  the 
  limestone 
  in 
  the 
  Oswe- 
  

   gatchie 
  series 
  ; 
  or 
  is 
  part 
  of 
  it, 
  and 
  if 
  so, 
  how 
  much, 
  older 
  and 
  

   unconformable 
  below 
  that 
  series 
  ? 
  Until 
  this 
  question 
  is 
  answered 
  

   it 
  is, 
  of 
  course, 
  impossible 
  to 
  prepare 
  a 
  map 
  of 
  the 
  region 
  which 
  

   shall 
  show 
  the 
  rocks 
  grouped 
  strictly 
  upon 
  a 
  time 
  basis. 
  The 
  

   difficulties 
  in 
  settling 
  the 
  matter 
  result 
  from 
  the 
  completeness 
  of 
  

   metamorphism. 
  The 
  gradual 
  transition 
  from 
  the 
  laminated 
  

   gneiss 
  into 
  the 
  massive 
  gneiss, 
  and 
  the 
  general 
  agreement 
  in 
  

   strike 
  and 
  dip 
  point 
  strongly 
  to 
  continuity 
  of 
  deposition. 
  But, 
  

   on 
  the 
  other 
  hand, 
  such 
  transition 
  and 
  agreement 
  in 
  structure 
  

  

  *Margerie 
  et 
  Heim, 
  Les 
  dislocations 
  de 
  TScorce 
  terrestre; 
  W. 
  H. 
  Hobbs, 
  Journal 
  of 
  Geology, 
  

   I, 
  p. 
  783. 
  

  

  