﻿454 
  Forty- 
  seventh 
  Report 
  on 
  the 
  State 
  Museum. 
  

  

  and 
  alluvial 
  deposits. 
  There 
  are 
  also 
  glacial 
  scratches 
  on 
  the 
  

   surface 
  of 
  all 
  of 
  the 
  harder 
  rocks. 
  The 
  glacial 
  drift 
  is 
  in 
  greater 
  

   part 
  scattered 
  over 
  the 
  higher 
  lands 
  in 
  masses 
  of 
  no 
  great 
  size 
  

   bat 
  occurring 
  at 
  frequent 
  intervals. 
  They 
  consist 
  of 
  loose 
  deposits 
  

   of 
  gravelly 
  sands 
  and 
  boulders 
  comprising 
  a 
  considerable 
  variety 
  

   of 
  rocks 
  which 
  occur 
  in 
  place 
  to 
  the 
  northward. 
  Crystalline 
  

   rocks 
  of 
  various 
  kinds 
  from 
  the 
  Adirondacks, 
  quartzites 
  and 
  sand- 
  

   stones, 
  limestones 
  and 
  more 
  or 
  less 
  local 
  material 
  are 
  found. 
  

   The 
  largest 
  deposit 
  is 
  on 
  the 
  plateau 
  of 
  Onondaga 
  limestone 
  north 
  

   of 
  Peoria 
  and 
  between 
  Feurabush 
  and 
  New 
  Salem. 
  There 
  are 
  

   also 
  a 
  number 
  of 
  accumulations 
  of 
  considerable 
  extent 
  in 
  the 
  

   Oniskethau 
  valley 
  north 
  of 
  Callanan's 
  Corners. 
  

  

  The 
  stratified 
  clays 
  and 
  sands 
  occupy 
  the 
  great 
  plain 
  of 
  the 
  

   Hudson 
  and 
  Mohawk 
  valleys. 
  The 
  clays 
  are 
  the 
  basal 
  member 
  

   and 
  the 
  sands 
  cap 
  them 
  to 
  a 
  greater 
  or 
  less 
  thickness. 
  The 
  extent 
  

   of 
  these 
  deposits 
  is 
  shown 
  on 
  the 
  colored 
  map. 
  They 
  lie 
  on 
  glacial 
  

   drift, 
  for 
  the 
  most 
  part 
  of 
  no 
  great 
  thickness, 
  and 
  on 
  the 
  glaciated 
  

   surface 
  of 
  the 
  Hudson 
  river 
  shales 
  and 
  sandstones. 
  Both 
  the 
  

   underlying 
  drift 
  and 
  rocks 
  extend 
  to 
  the 
  surface 
  in 
  some 
  localities 
  

   as 
  islands 
  where 
  the 
  clays 
  and 
  sands 
  were 
  deposited 
  around 
  them. 
  

   These 
  clays 
  and 
  sands 
  were 
  deposited 
  in 
  the 
  Champlain 
  period, 
  

   which 
  followed 
  the 
  last 
  glacial 
  invasion 
  of 
  the 
  region. 
  This 
  

   period 
  was 
  one 
  of 
  submergence, 
  in 
  which 
  the 
  waters 
  of 
  the 
  Hud- 
  

   son 
  and 
  Mohawk 
  rivers 
  extended 
  far 
  above 
  their 
  present 
  levels 
  

   and 
  overflowed 
  all 
  the 
  country 
  west 
  to 
  the 
  Helderberg 
  escarp- 
  

   ment 
  or 
  the 
  hills 
  adjoining 
  it 
  to 
  the 
  east 
  and 
  north. 
  In 
  the 
  pre- 
  

   ceding 
  figure 
  the 
  approximate 
  extent 
  of 
  this 
  submergence 
  is 
  

   represented. 
  

  

  The 
  shores 
  to 
  which 
  this 
  submergence 
  extended 
  are 
  strikingly 
  

   exhibited 
  throughout, 
  in 
  greater 
  part 
  rising 
  steeply 
  from 
  the 
  plain. 
  

   On 
  the 
  east 
  side 
  of 
  the 
  Hudson 
  they 
  were 
  very 
  irregular, 
  and 
  

   there 
  were 
  numerous 
  islands 
  and 
  promontories. 
  To 
  the 
  west- 
  

   ward 
  the 
  course 
  was 
  relatively 
  straight, 
  but 
  the 
  waters 
  extended 
  

   up 
  the 
  Hannacrois 
  and 
  Oniskethau 
  creeks 
  for 
  a 
  considerable 
  

   distance. 
  To 
  the 
  northward 
  there 
  were 
  open 
  waters 
  to 
  Lake 
  

   George 
  and 
  Lake 
  Champlain 
  over 
  a 
  wide 
  area. 
  

  

  Near 
  South 
  Bethlehem 
  and 
  Altamont 
  there 
  are 
  extensive 
  delta 
  

   deposits 
  of 
  sands 
  and 
  gravels 
  laid 
  down 
  by 
  the 
  Oniskethau 
  and 
  

  

  