﻿14 
  NEW 
  YORK 
  STATE 
  MUSEUM 
  

  

  Taconic 
  disturbance 
  is 
  most 
  apparent 
  in 
  the 
  eastern 
  part 
  of 
  the 
  

   State 
  where 
  there 
  exists 
  a 
  strong 
  erosional 
  unconformity 
  between 
  

   the 
  Lower 
  and 
  the 
  Upper 
  Siluric 
  that 
  is 
  well 
  marked 
  also 
  by 
  basal 
  

   conglomerates 
  (Oneida, 
  Skunnemunk 
  and 
  Shawangunk).; 
  its 
  appar- 
  

   ent 
  influence 
  can 
  not 
  be 
  traced 
  farther 
  west 
  than 
  Oswego 
  county, 
  as 
  

   Vanuxem 
  1 
  has 
  noted 
  that 
  no 
  break 
  occurs 
  in 
  the 
  succession 
  from 
  the 
  

   Lower 
  Siluric 
  to 
  the 
  Oswego 
  sandstone 
  of 
  that 
  section. 
  

  

  The 
  Upper 
  Siluric 
  formations, 
  for 
  the 
  most 
  part, 
  have 
  the 
  char- 
  

   acters 
  of 
  shallow 
  water 
  accumulations. 
  In 
  the 
  basal 
  members 
  sand- 
  

   stones 
  and 
  conglomerates 
  prevail 
  and 
  are 
  made 
  up 
  of 
  the 
  coarser 
  

   quartzose 
  detritus 
  from 
  the 
  wash 
  of 
  the 
  nearby 
  land. 
  Some 
  finer 
  

   sands 
  and 
  muds 
  were 
  brought 
  down 
  and 
  deposited 
  during 
  Medina 
  

   time 
  to 
  form 
  the 
  shales 
  which 
  are 
  interbedded 
  with 
  the 
  sandstones, 
  

   but 
  it 
  was 
  not 
  until 
  Clinton 
  time 
  that 
  they 
  came 
  to 
  be 
  the 
  predomi- 
  

   nant 
  material. 
  During 
  this 
  and 
  the 
  succeeding 
  Rochester 
  ages 
  silts 
  

   were 
  accumulated 
  in 
  great 
  thickness, 
  though 
  there 
  were 
  brief 
  periods 
  

   in 
  the 
  Clinton 
  when 
  they 
  gave 
  way 
  to 
  limestones 
  and 
  in 
  eastern 
  

   New 
  York 
  to 
  calcareous 
  sandstones. 
  With 
  the 
  beginning 
  of 
  Lock- 
  

   port 
  time 
  the 
  conditions 
  of 
  sedimentation 
  became 
  favorable 
  to 
  the 
  

   deposition 
  of 
  limestones 
  and 
  these 
  rocks 
  were 
  laid 
  down 
  all 
  through 
  

   the 
  rest 
  of 
  the 
  Upper 
  Siluric, 
  with 
  one 
  notable 
  interruption 
  repre- 
  

   sented 
  by 
  the 
  Salina 
  shales. 
  The 
  changes 
  in 
  the 
  character 
  of 
  the 
  

   sedimentation 
  are 
  to 
  be 
  regarded, 
  doubtless, 
  as 
  reflecting 
  a 
  certain 
  

   amount 
  of 
  coastal 
  oscillation 
  which 
  produced 
  shallowing 
  or 
  deepen- 
  

   ing 
  of 
  the 
  waters 
  adapted 
  to 
  the 
  different 
  deposits. 
  It 
  is 
  not 
  neces- 
  

   sary 
  to 
  suppose, 
  however, 
  that 
  the 
  shales 
  and 
  limestones 
  required 
  

   any 
  great 
  depths 
  for 
  their 
  accumulation. 
  On 
  the 
  other 
  hand 
  there 
  

   are 
  unmistakable 
  evidences 
  that 
  they 
  were 
  laid 
  down 
  for 
  the 
  most 
  

   part 
  within 
  the 
  littoral 
  reign. 
  The 
  Clinton 
  and 
  many 
  of 
  the 
  over- 
  

   lying 
  limestones 
  are 
  of 
  fragmental 
  character, 
  composed 
  of 
  fossils 
  

   that 
  were 
  washed 
  up 
  on 
  the 
  old 
  beaches 
  where 
  they 
  were 
  worked 
  

   over 
  and 
  ground 
  by 
  wave 
  action. 
  Abundant 
  beach 
  markings, 
  such 
  

   as 
  ripple 
  marks, 
  shrinkage 
  cracks, 
  worm 
  borings 
  and 
  tracks 
  of 
  

   crustaceans 
  are 
  to 
  be 
  found 
  in 
  the 
  shales. 
  

  

  During 
  Clinton 
  time 
  there 
  seems 
  to 
  have 
  been 
  an 
  approach 
  to 
  the 
  

   conditions 
  which 
  later 
  in 
  the 
  Salina 
  age 
  led 
  to 
  the 
  extensive 
  deposi- 
  

   tion 
  of 
  salt 
  and 
  gypsum. 
  These 
  conditions 
  may 
  have 
  been 
  initiated 
  

   even 
  as 
  early 
  as 
  Medina 
  time. 
  Salt 
  springs 
  are 
  found 
  not 
  infre- 
  

   quently 
  along 
  the 
  outcrop 
  of 
  the 
  Medina 
  sandstones 
  and 
  in 
  such 
  a 
  

   state 
  of 
  concentration 
  that 
  they 
  were 
  once 
  used 
  commercially 
  for 
  

  

  1 
  Geol. 
  N. 
  Y. 
  3d 
  Dist. 
  1842. 
  p. 
  61 
  et 
  seq. 
  

  

  