﻿120 
  NEW 
  YORK 
  STATE 
  MUSEUM 
  

  

  zones 
  have 
  been 
  noted 
  in 
  the 
  Paleozoic 
  rocks, 
  and 
  the 
  deforma- 
  

   tion 
  which 
  gave 
  rise 
  to 
  them 
  seems 
  certainly 
  of 
  Precambric 
  date, 
  

   though 
  later 
  than 
  that 
  previously 
  described 
  since 
  the 
  rocks 
  were 
  

   linder 
  less 
  load, 
  hence 
  nearer 
  the 
  surface. 
  

  

  In 
  the 
  Paleozoic 
  rocks. 
  Frequent 
  faults 
  of 
  small 
  throw 
  may 
  be 
  

   made 
  out 
  in 
  the 
  Potsdam 
  sandstone. 
  The 
  red 
  and 
  white 
  banded 
  

   stone 
  which 
  constitutes 
  the 
  lower 
  part 
  of 
  the 
  formation 
  on 
  the 
  

   Alexandria 
  quadrangle 
  is 
  excellently 
  adapted 
  to 
  display 
  them, 
  

   and 
  a 
  magnificent 
  exhibit 
  of 
  them 
  is 
  given 
  on 
  the 
  bare 
  rock 
  surface 
  

   of 
  the 
  large 
  Potsdam 
  outlier 
  which 
  lies 
  between 
  the 
  railroad 
  and 
  the 
  

   north 
  end 
  of 
  Butterfield 
  lake. 
  Here 
  over 
  a 
  considerable 
  area 
  the 
  

   faults 
  are 
  spaced 
  but 
  a 
  few 
  feet 
  apart, 
  and 
  though 
  the 
  throw 
  seldom 
  

   amounts 
  to 
  as 
  much 
  as 
  a 
  foot^ 
  and 
  is 
  frequently 
  only 
  a 
  fraction 
  of 
  

   an 
  inch, 
  the 
  combined 
  displacement 
  of 
  the 
  whole 
  must 
  be 
  quite 
  con- 
  

   siderable, 
  as 
  there 
  are 
  hundreds 
  of 
  them. 
  For 
  a 
  hand 
  specimen 
  from 
  

   this 
  locality, 
  showing 
  one 
  of 
  these 
  faults 
  see 
  plate 
  31, 
  upper 
  figure. 
  

   All 
  noted 
  are 
  normal 
  faults 
  of 
  slight 
  hade. 
  The 
  fault 
  planes 
  are 
  

   'filled 
  with 
  sand 
  grains 
  in 
  all 
  respects 
  like 
  those 
  of 
  the 
  rock 
  itself 
  and 
  

   as 
  thoroughly 
  cemented, 
  which 
  would 
  seem 
  to 
  indicate 
  that 
  the 
  

   faulting 
  occurred 
  before 
  rock 
  cementation 
  was 
  far 
  advanced, 
  so 
  that 
  

   the 
  grains 
  gave 
  way 
  individually 
  instead 
  of 
  as 
  sandstone 
  fragments, 
  

   whereas 
  the 
  latter 
  would 
  certainly 
  be 
  the 
  method 
  were 
  faulting 
  to 
  

   take 
  place 
  in 
  the 
  rock 
  now. 
  Cementation 
  subsequent 
  to 
  the 
  faulting 
  

   has 
  thoroughly 
  indurated 
  the 
  whole. 
  

  

  The 
  bulk 
  of 
  the 
  formation 
  is 
  rather 
  uniformly 
  colored 
  and 
  

   hence 
  not 
  so 
  well 
  adapted 
  to 
  display 
  faulting 
  of 
  this 
  type, 
  and 
  it 
  

   is 
  not 
  certain 
  whether 
  it 
  occurs 
  in 
  it 
  or 
  not. 
  

  

  There 
  are 
  also 
  occasional 
  small 
  faults 
  of 
  a 
  later 
  type 
  in 
  the 
  

   Potsdam, 
  the 
  fault 
  planes 
  remaining 
  as 
  open 
  cracks, 
  with 
  sand- 
  

   stone 
  fragments 
  in 
  the 
  fault 
  breccias. 
  A 
  small 
  fault 
  of 
  this 
  type 
  

   appears 
  in 
  plate 
  12. 
  

  

  In 
  the 
  limestones 
  a 
  few 
  faults 
  have 
  been 
  noted 
  whose 
  throw 
  

   amounts 
  to 
  several 
  feet. 
  The 
  best 
  example 
  seen 
  by 
  the 
  writer 
  

   is 
  in 
  the 
  lower 
  Pamelia 
  limestones 
  of 
  the 
  Pamelia 
  inface, 
  2 
  miles 
  

   east 
  of 
  Perch 
  lake. 
  The 
  section 
  here 
  shows 
  the 
  basal, 
  black, 
  

   fossiliferous 
  limestones, 
  overlaid 
  by 
  a 
  thickness 
  of 
  some 
  15 
  feet 
  of 
  

   thin 
  bedded, 
  earthy 
  limestone, 
  followed 
  in 
  its 
  turn 
  by 
  massive 
  

   blue 
  limestone 
  wath 
  interbedded 
  gray 
  magnesian 
  layers. 
  These 
  

   upper 
  massive 
  limestones 
  are 
  faulted 
  down 
  against 
  the 
  earthy 
  

   limestone, 
  the 
  fault 
  bearing 
  n. 
  30° 
  e, 
  doAvnthrowing 
  to 
  the 
  east 
  

   and 
  with 
  a 
  throw 
  of 
  some 
  20 
  feet. 
  

  

  