﻿l6 
  NEW 
  YORK 
  STATE 
  MUSEUM 
  

  

  The 
  Theresa 
  formation 
  followed 
  close 
  after 
  the 
  Potsdam 
  and 
  

   they 
  were 
  laid 
  down 
  in 
  a 
  trough 
  or 
  bay 
  along 
  the 
  present 
  St 
  

   Lawrence 
  line 
  which 
  w^as 
  landlocked 
  on 
  the 
  north, 
  south 
  and 
  

   west. 
  The 
  depression 
  of 
  this 
  trough 
  originated 
  to 
  the 
  eastward, 
  

   where 
  the 
  deposits 
  are 
  thickest, 
  and 
  deposits 
  did 
  not 
  commence 
  

   in 
  the 
  immediate 
  region 
  until 
  late 
  in 
  Potsdam 
  time. 
  The 
  ex- 
  

   ireme 
  western 
  extremity 
  of 
  the 
  bay 
  can 
  not 
  have 
  lain 
  many 
  miles 
  

   west 
  of 
  the 
  immediate 
  region 
  at 
  the 
  time 
  of 
  its 
  greatest 
  expan- 
  

   sion. 
  Then 
  it 
  commenced 
  to 
  contract 
  and 
  slowly 
  work 
  back 
  east- 
  

   ward.^ 
  

  

  Uplift 
  following 
  the 
  Theresa. 
  This 
  tendency 
  to 
  contraction 
  

   of 
  the 
  trough, 
  caused 
  by 
  slow 
  uplift 
  of 
  the 
  land, 
  seems 
  to 
  have 
  

   continued 
  until 
  the 
  bottoms 
  of 
  both 
  the 
  St 
  Lawrence 
  and 
  the 
  

   Champlain 
  troughs 
  had 
  been 
  raised 
  above 
  sea 
  level, 
  so 
  that 
  all 
  

   the 
  northern 
  portion 
  of 
  the 
  State 
  was 
  above 
  that 
  level. 
  After 
  a 
  

   time 
  renewed 
  depression 
  followed, 
  apparently 
  commencing 
  simul- 
  

   taneously 
  on 
  the 
  west, 
  sou'h 
  and 
  east 
  sides 
  of 
  the 
  Adirondacks, 
  and 
  

   the 
  Tribes 
  Hill 
  phase 
  of 
  the 
  Beekmantoiwn 
  formation 
  was 
  laid 
  

   down. 
  This 
  was 
  followed 
  by 
  uplift 
  which 
  began 
  at 
  the 
  west 
  and 
  

   worked 
  eastward, 
  bringing 
  the 
  west 
  and 
  south 
  sides 
  of 
  the 
  district 
  

   above 
  sea 
  level, 
  while 
  subsidence 
  still 
  continued 
  in 
  the 
  Champlain 
  

   valley, 
  in 
  which 
  a 
  large 
  thickness 
  of 
  later 
  Beekmantown 
  rocks 
  

   was 
  deposited. 
  This 
  Tribes 
  Hill 
  subsidence 
  came 
  in 
  on 
  our 
  dis- 
  

   trict 
  here 
  from 
  the 
  south 
  and 
  its 
  deposits 
  constitute 
  the 
  upper 
  

   portion 
  of 
  what 
  is 
  mapped 
  as 
  the 
  Theresa 
  formation. 
  Until 
  the 
  

   Beekmantown 
  formation 
  along 
  the 
  St 
  Lawrence 
  valley 
  has 
  received 
  

   further 
  study 
  we 
  can 
  not 
  say 
  whether 
  the 
  Tribes 
  Hill 
  limestone 
  

   extends 
  east 
  of 
  the 
  Frontenac 
  axis 
  or 
  not. 
  Our 
  present 
  view 
  is 
  

   that 
  it 
  did 
  not, 
  and 
  that 
  the 
  Beekmantown 
  of 
  the 
  St 
  Lawrence 
  

   valley 
  represents 
  the 
  higher 
  portion 
  of 
  the 
  formation, 
  deposited 
  

   in 
  a 
  trough 
  which 
  extended 
  westward 
  up 
  the 
  valley 
  from 
  the 
  

   Champlain 
  basin. 
  This 
  depression 
  did 
  not 
  carry 
  the 
  immediate 
  

   region 
  below 
  sea 
  level. 
  The 
  district 
  tilted 
  to 
  the 
  southwest 
  and 
  

   received 
  a 
  thin 
  edge 
  of 
  Tribes 
  Hill 
  deposition, 
  then 
  rose 
  and 
  was 
  

   tilted 
  back 
  to 
  the 
  eastward, 
  though 
  not 
  sufficiently 
  to 
  allow 
  the 
  

   later 
  Beekmantown 
  sea 
  of 
  the 
  district 
  to 
  the 
  east 
  to 
  quite 
  reach 
  it. 
  

  

  1- 
  Since 
  the 
  field 
  work 
  was 
  completed 
  and 
  this 
  report 
  written, 
  work 
  else- 
  

   where 
  in 
  New 
  York 
  has 
  shown 
  that 
  probably 
  the 
  Theresa 
  formation, 
  as 
  

   here 
  mapped 
  and 
  described, 
  is 
  in 
  reality 
  composed 
  of 
  two 
  probably 
  

   unconformable 
  formations, 
  of 
  quite 
  different 
  ag-es, 
  and 
  that 
  the 
  name 
  

   should 
  be 
  restricted 
  to 
  the 
  lowermost 
  of 
  these, 
  the 
  upper 
  bein^ 
  of 
  lower 
  

   Beekmantown 
  age, 
  and 
  equivalent 
  to 
  what 
  we 
  are 
  calling 
  the 
  Tribes 
  Hill 
  

   formation 
  in 
  the 
  Mohawk 
  valley. 
  The 
  matter 
  is 
  discussed 
  in 
  more 
  detail 
  on 
  

   a 
  later 
  page. 
  

  

  