﻿464 
  Forty-seventh 
  Report 
  on 
  the 
  State 
  Museum. 
  

  

  that 
  the~more 
  or 
  less 
  torrential 
  conditions 
  under 
  which 
  the 
  gravel 
  

   beds 
  were 
  deposited 
  had 
  given 
  way 
  to 
  a 
  slower 
  subsidence. 
  

   During 
  this 
  subsidence 
  deep 
  gorges 
  had 
  been 
  cut 
  in 
  the 
  gravel 
  

   beds, 
  in 
  many 
  places 
  quite 
  down 
  to 
  the 
  underlying 
  rock 
  beds. 
  

   Then, 
  during 
  the 
  quiet, 
  and 
  probably 
  deeper 
  waters, 
  the 
  clays 
  

   were 
  deposited, 
  quite 
  filling 
  these 
  depressions. 
  That 
  the 
  clays 
  

   were 
  deposited 
  during 
  a 
  slow 
  subsidence 
  is 
  beautifully 
  shown 
  by 
  

   phenomena 
  which 
  are 
  visible 
  in 
  many 
  clay 
  banks 
  now 
  being 
  

   worked. 
  Fig. 
  1 
  is 
  a 
  view 
  of 
  a 
  clay 
  bank 
  just 
  south 
  of 
  the 
  

   Knickerbocker 
  icehouse 
  at 
  Coeymans. 
  Here 
  a 
  large 
  bank 
  of 
  

  

  R 
  s 
  .r 
  

  

  

  "••** 
  \:\. 
  **•*..• 
  •., 
  / 
  

  

  uect"io7p 
  of 
  Clay 
  Scuhh 
  

   ohovrina 
  "fine 
  sandy 
  Oayers 
  Qra-cfuaZZy 
  ha&siiuo 
  

   into 
  fcot 
  clcby. 
  

  

  sand 
  divides 
  to 
  the 
  surface 
  of 
  the 
  clay 
  beds 
  lying 
  on 
  either 
  side 
  

   of 
  it. 
  The 
  sand 
  bank 
  itself 
  is 
  of 
  coarse 
  cross-bedded 
  gravels. 
  

   Just 
  where 
  the 
  clay 
  would 
  naturally 
  come 
  in 
  contact 
  with 
  the 
  

   sand 
  or 
  gravel 
  the 
  entire 
  mass 
  is 
  made 
  up 
  of 
  fine 
  argillaceous 
  

   sandy 
  layers 
  as 
  distinctly 
  laminated 
  as 
  on 
  the 
  clays. 
  Going 
  

   south 
  from 
  this 
  point 
  the 
  argillaceous 
  sand 
  gives 
  place 
  gradually 
  

   to 
  layers 
  of 
  clay 
  with 
  fine 
  sand 
  and 
  within 
  fifty 
  to 
  one 
  hundred 
  

   feet 
  fat 
  clays 
  are 
  found 
  exclusively. 
  In 
  other 
  words 
  the 
  fat 
  clay 
  

   gradually 
  changes 
  to 
  fine 
  sand 
  as 
  the 
  contact 
  with 
  the 
  gravel 
  

   beds 
  is 
  approached. 
  These 
  phenomena 
  may 
  be 
  observed 
  in 
  

   many 
  of 
  the 
  clay 
  banks 
  of 
  South 
  Albany. 
  From 
  the 
  above 
  facts 
  

   it 
  seems 
  reasonable 
  to 
  inf 
  er 
  j 
  that 
  during 
  the 
  disposition 
  of 
  the 
  

  

  