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  NEW 
  YOKK 
  STATE 
  MUSEUM 
  

  

  The 
  Onondaga-salt 
  group 
  is 
  hardly 
  seen 
  in 
  New 
  York 
  east 
  of 
  

   Herkimer 
  county. 
  The 
  succeeding 
  formation, 
  however, 
  which 
  is 
  

   grouped 
  with 
  the 
  Salina 
  is 
  fairly 
  persistent. 
  

  

  Waterlime 
  

   Overlying 
  the 
  salt-bearing 
  rocks 
  and 
  forming 
  with 
  them 
  the 
  On- 
  

   ondaga 
  group 
  is 
  the 
  Waterlime, 
  a 
  succession 
  of 
  dark-colored, 
  fine- 
  

   grained 
  and 
  straight-bedded 
  layers 
  of 
  limestone, 
  attaining 
  in 
  Mad- 
  

   ison 
  county 
  a 
  thickness 
  of 
  over 
  100 
  feet. 
  It 
  lies 
  immediately 
  over 
  

   the 
  gray 
  and 
  drab 
  limestones 
  of 
  the 
  upper 
  part 
  of 
  the 
  salt 
  group, 
  

   and 
  is 
  not 
  divided 
  from 
  them 
  by 
  any 
  very 
  distinct 
  or 
  sudden 
  

   change 
  in 
  the 
  appearance 
  of 
  the 
  strata. 
  The 
  name 
  is 
  given 
  from 
  

   the 
  waterlime 
  or 
  hydraulic 
  cement 
  which 
  is 
  extensively 
  manufac- 
  

   tured 
  from 
  two 
  of 
  the 
  layers 
  toward 
  their 
  upper 
  part: 
  these 
  are 
  

   generally 
  of 
  a 
  drab 
  color, 
  and 
  separated 
  from 
  each 
  other 
  by 
  a 
  

   thin 
  mass 
  of 
  blue 
  limestone. 
  They 
  are 
  quarried, 
  burnt 
  and 
  ground 
  

   on 
  a 
  very 
  large 
  scale 
  near 
  Manlius 
  in 
  Onondaga 
  county, 
  and 
  the 
  

   hydraulic 
  cement 
  of 
  Rosendale 
  and 
  Rondout 
  is 
  made 
  from 
  the 
  

   same 
  beds. 
  That 
  manufactured 
  at 
  Williamsville, 
  Erie 
  county, 
  

   and 
  at 
  Buffalo, 
  is 
  from 
  the 
  upper 
  limestones 
  of 
  the 
  Salina 
  group 
  

   below; 
  and 
  in 
  Niagara 
  and 
  Orleans 
  counties, 
  a 
  similar 
  cement 
  is 
  

   made 
  from 
  some 
  layers 
  of 
  the 
  Niagara 
  group. 
  

  

  HELDERBERG 
  ROCKS 
  

  

  Above 
  the 
  formations 
  already 
  described 
  succeeds 
  a 
  thick 
  series 
  

   of 
  strata, 
  chiefly 
  limestone, 
  separated 
  by 
  sandstone 
  and 
  grit 
  rocks, 
  

   first 
  described 
  under 
  the 
  general 
  name 
  of 
  the 
  Helderberg 
  rocks, 
  

   as 
  they 
  formed 
  the 
  great 
  escarpment 
  of 
  the 
  Helderberg 
  moun- 
  

   tains 
  in 
  Albany 
  county. 
  From 
  this 
  place 
  their 
  edges 
  may 
  be 
  

   followed 
  southward 
  in 
  the 
  hills 
  lying 
  west 
  of 
  the 
  Hudson 
  river, 
  

   past 
  the 
  base 
  of 
  theCatskill 
  mountains, 
  and 
  through 
  Ulster 
  county 
  

   as 
  far 
  as 
  Kingston 
  and 
  Rondout; 
  whence 
  their 
  outcrops 
  bend 
  

   south 
  westward 
  and 
  extend 
  along 
  the 
  hills 
  w^est 
  of 
  the 
  valley 
  of 
  the 
  

   Delaware 
  and 
  Hudson 
  canal, 
  passing 
  out 
  of 
  the 
  state 
  near 
  the 
  

   northwest 
  corner 
  of 
  New 
  Jersey. 
  They 
  run 
  still 
  farther 
  south- 
  

   westward, 
  are 
  seen 
  above 
  the 
  Delaware 
  Water 
  Gap, 
  and 
  their 
  

  

  