﻿68 
  NEW 
  YORK 
  STATE 
  MUSEUM 
  

  

  work 
  is 
  only 
  begun 
  we 
  are 
  strong 
  in 
  our 
  belief 
  that 
  uplift 
  of 
  the 
  

   whole 
  region 
  preceded 
  the 
  Beekmantown. 
  

  

  The 
  type 
  locality 
  of 
  the 
  formation, 
  at 
  Potsdam, 
  is 
  precisely 
  

   midway 
  between 
  Clayton 
  and 
  Lake 
  Champlain. 
  ' 
  If 
  one 
  of 
  these 
  

   ends 
  is 
  of 
  Potsdam, 
  and 
  the 
  other 
  of 
  Beekmantown 
  age, 
  it 
  is 
  of 
  

   interest 
  to 
  conjecture 
  what 
  the 
  age 
  may 
  be 
  at 
  the 
  type 
  locality. 
  

  

  To 
  the 
  writer 
  it 
  has 
  long 
  seemed 
  clear 
  that 
  the 
  sandstone 
  and 
  

   the 
  overlying 
  dolomite 
  must 
  be 
  classed 
  in 
  the 
  same 
  period, 
  not 
  

   only 
  here 
  on 
  the 
  west 
  but 
  everywhere 
  in 
  northern 
  Xew 
  York. 
  

   By 
  the 
  overlying 
  dolomite 
  is 
  meant 
  not 
  the 
  true 
  Beekmantown 
  

   formation, 
  but 
  the 
  dolomites 
  which 
  underlie 
  this 
  and 
  which, 
  the 
  

   evidence 
  indicates, 
  underlie 
  it 
  everywhere 
  unconformably. 
  These 
  

   dolomites 
  have" 
  heretofore 
  been, 
  classed 
  Avith 
  the 
  Beekmantown 
  

   and 
  constitute 
  Brainard 
  and 
  Seely's 
  " 
  Division 
  A" 
  of 
  that 
  forma- 
  

   tion 
  in 
  the 
  Champlain 
  valley, 
  with 
  the 
  underlying 
  " 
  passage 
  

   beds.'' 
  But 
  while 
  the 
  beds 
  of 
  this 
  division 
  grade 
  downward 
  into 
  

   the 
  Potsdam 
  they 
  are 
  separated 
  by 
  an 
  unconformity 
  from 
  the 
  

   beds 
  of 
  '■' 
  Division 
  B 
  " 
  just 
  above, 
  as 
  recently 
  shown 
  by 
  Ulrich; 
  be- 
  

   cause 
  of 
  which 
  the 
  writer 
  has 
  recently 
  argued 
  that, 
  since 
  this 
  

   unconformity 
  is 
  everywhere 
  present 
  in 
  Xew 
  York, 
  marking 
  the 
  

   emergence 
  of 
  the 
  entire 
  region, 
  it 
  forms 
  the 
  logical 
  plane 
  of 
  

   division 
  between 
  the 
  Ordovicic 
  and 
  the 
  group 
  beneath. 
  If 
  this 
  

   contention 
  be 
  well 
  founded, 
  the 
  Potsdam 
  and 
  Theresa 
  formations, 
  

   the 
  Little 
  Falls 
  dolomite, 
  and 
  '' 
  Division 
  A," 
  fall 
  into 
  the 
  upper 
  

   Cambric 
  group 
  of 
  present 
  classifications. 
  Ulrich 
  has, 
  however, 
  

   recently 
  proposed 
  a 
  different 
  classification, 
  involving 
  the 
  in- 
  

   sertion 
  of 
  a 
  new 
  group 
  of 
  period 
  rank 
  between 
  the 
  Cambric 
  and 
  

   Ordovicic, 
  for 
  which 
  he 
  proposes 
  the 
  name 
  '' 
  Ozarkic," 
  and 
  into 
  

   which 
  the 
  Potsdam 
  and 
  Theresa 
  formations 
  would 
  fall. 
  For 
  

   many 
  reasons 
  the 
  writer 
  is 
  in 
  accord 
  with 
  tliis 
  suggested 
  innovation. 
  

  

  Pamelia 
  formation 
  

  

  In 
  our 
  district 
  here 
  the 
  Theresa 
  formation 
  is 
  everywhere 
  over- 
  

   laid 
  by 
  the 
  limestone 
  group 
  here 
  called 
  the 
  Pamelia 
  formation. 
  

   This 
  is 
  in 
  some 
  respects 
  the 
  most 
  interesting 
  formation 
  in 
  the 
  

   section 
  since 
  it 
  represents 
  the 
  thinned, 
  shoreward 
  edge 
  of 
  a 
  

   formation 
  which, 
  while 
  widepread 
  elsewhere, 
  has 
  not 
  hereto- 
  

   fore 
  been 
  recognized 
  in 
  New 
  York, 
  and 
  is 
  in 
  existence 
  as 
  a 
  sur- 
  

   face 
  formation 
  in 
  the 
  State 
  only 
  in 
  this 
  immediate 
  area. 
  Be- 
  

   cause 
  of 
  its 
  wide 
  separation 
  from 
  other 
  areas 
  where 
  the 
  forma- 
  

   tion 
  appears, 
  and 
  because 
  it 
  represents 
  only 
  a 
  local 
  facies 
  of 
  the 
  

  

  