﻿I70 
  

  

  NEW 
  YORK 
  STATE 
  MUSEUM 
  

  

  project 
  into 
  the 
  Niagaran 
  Rochester 
  shale. 
  One 
  may 
  then 
  find, 
  on 
  

   abraded 
  surfaces, 
  as 
  at 
  Lockport, 
  the 
  lens 
  contrasting 
  as 
  a 
  white 
  

   inlier 
  with 
  the 
  dark 
  shale 
  [see 
  text 
  fig. 
  6, 
  7]. 
  

  

  2 
  Erosion 
  inliers. 
  We 
  distinguish 
  in 
  this 
  class 
  between 
  corra- 
  

   sioiL 
  inliers 
  which 
  have 
  resulted 
  from 
  river 
  corrasion 
  ; 
  solution 
  

   inliers; 
  and 
  glacial 
  erosion 
  inliers 
  in 
  which 
  the 
  ice 
  is 
  thought 
  to 
  

   have 
  been 
  the 
  exposing 
  agent. 
  

  

  Fig. 
  8 
  Inlier 
  of 
  Lowville 
  limestone 
  

   River 
  limestone 
  SSS 
  

  

  in 
  Black 
  

  

  at 
  the 
  head 
  of 
  Gufifin 
  bay 
  

  

  Jefferson 
  county, 
  N. 
  Y. 
  Scale 
  i 
  m. 
  := 
  i 
  in. 
  

  

  a 
  Corrasion 
  inliers. 
  The 
  first 
  group 
  we 
  have 
  found 
  excellently 
  

   exemplified 
  in 
  small 
  and 
  simple 
  forms 
  in 
  the 
  southern 
  portion 
  of 
  the 
  

   Clayton 
  sheet. 
  As 
  the 
  sketch 
  maps 
  inserted 
  indicate 
  [see 
  text 
  

   fig. 
  8, 
  9, 
  10], 
  these 
  inliers 
  consist 
  of 
  strips 
  of 
  Lowville 
  limestone 
  ex- 
  

   posed 
  along 
  brooks 
  and 
  surrounded 
  on 
  all 
  sides 
  by 
  Black 
  River 
  

   limestone. 
  The 
  conditions 
  which 
  have 
  produced 
  this 
  peculiar 
  form 
  

   of 
  inher 
  — 
  which 
  judging 
  from 
  our 
  maps 
  is 
  very 
  rarely 
  seen 
  in 
  

   other 
  paits 
  of 
  the 
  State 
  — 
  are 
  the 
  following: 
  The 
  coincidence 
  

   of 
  the 
  dip 
  of 
  the 
  beds 
  and 
  of 
  the 
  course 
  of 
  the 
  brook 
  and 
  a 
  resist- 
  

   ance 
  of 
  the 
  underlying 
  Lowville 
  limestone 
  to 
  erosion 
  that 
  is 
  greater 
  

   than 
  that 
  of 
  the 
  Black 
  River 
  beds. 
  The 
  brook, 
  as 
  a 
  rule, 
  reaches 
  

   the 
  inlier 
  by 
  a 
  fall 
  and 
  finally 
  leaves 
  it 
  by 
  very 
  gradually 
  passing 
  

   again 
  upon 
  the 
  overlying 
  rock 
  [sec 
  text 
  fig. 
  10, 
  p. 
  172]. 
  That 
  

   means 
  that 
  for 
  some 
  distance 
  the 
  gradient 
  of 
  the 
  brook 
  is 
  

  

  