﻿68 
  NEW 
  YORK 
  STATE 
  MUSEUM 
  

  

  varying 
  in 
  diameter 
  up 
  to 
  6 
  inches 
  or 
  a 
  foot. 
  The 
  stratification 
  is 
  

   rude, 
  and 
  shells 
  are 
  abundant. 
  These 
  are 
  mostly 
  fresh-water 
  mus- 
  

   sels 
  (Unio, 
  Alasmodonta, 
  etc.) 
  and 
  the 
  valves 
  are 
  generally 
  

   found 
  in 
  conjunction, 
  a 
  fact 
  which 
  may 
  indicate 
  that 
  these 
  shells 
  

   lived 
  here. 
  Small 
  gastropod 
  and 
  pelecypod 
  shells 
  are 
  plentifully 
  

   mingled 
  with 
  the 
  pebbles 
  and 
  sai'.ds. 
  Below 
  this 
  are 
  coarser 
  de- 
  

   posits 
  where 
  boulders 
  up 
  to 
  several 
  feet 
  in 
  diameter 
  occur, 
  and 
  below 
  

   this 
  occurs 
  a 
  bluish 
  clay. 
  In 
  all 
  of 
  these 
  beds 
  shells 
  have 
  been 
  

   sparingly 
  found. 
  

  

  Several 
  excavations 
  have 
  been 
  made 
  in 
  Queen 
  Victoria 
  park, 
  and 
  

   here 
  shells 
  are 
  common. 
  The 
  Unionidae 
  appear 
  to 
  be 
  most 
  abund- 
  

   ant, 
  though 
  small 
  gastropods 
  are 
  not 
  uncommon. 
  All 
  appear 
  to 
  

   have 
  been 
  more 
  or 
  less 
  waterworn. 
  The 
  mussel 
  shells 
  are 
  gen- 
  

   erally 
  decayed, 
  ov/ing 
  no 
  doubt 
  to 
  percolating 
  waters. 
  Below 
  Clif- 
  

   ton, 
  the 
  lower 
  of 
  two 
  terraces 
  is 
  of 
  a 
  somewhat 
  sandy 
  character, 
  

   though 
  many 
  boulders 
  occur 
  in 
  it. 
  Shells 
  of 
  unios 
  occur 
  sparingly 
  

   in 
  these 
  deposits, 
  and 
  a 
  few 
  small 
  gastropods 
  were 
  found 
  in 
  the 
  

   lowest 
  terrace. 
  Farther 
  north 
  several 
  excavations 
  in 
  the 
  lower 
  ter- 
  

   races 
  of 
  the 
  old 
  river 
  show 
  loose 
  gravels 
  alternating 
  with 
  a 
  sort 
  of 
  

   till, 
  a 
  few 
  Goniobasis 
  and 
  other 
  gastropod 
  shells 
  being 
  found 
  

   here. 
  In 
  some 
  cases 
  the 
  gravels 
  have 
  become 
  cemented 
  into 
  a 
  con- 
  

   glomerate 
  by 
  a 
  deposit 
  of 
  calcite 
  between 
  them, 
  often 
  of 
  consider- 
  

   able 
  thickness. 
  Boulders 
  of 
  similarly 
  cemented 
  gravels 
  are 
  found 
  

   in 
  the 
  gorge 
  below, 
  at 
  the 
  whirlpool. 
  

  

  It 
  will 
  thus 
  be 
  seen 
  that, 
  throughout 
  the 
  greater 
  part 
  of 
  the 
  young 
  

   Niagara, 
  deposition 
  was 
  going 
  on 
  as 
  well 
  as 
  erosion. 
  The 
  amount 
  

   of 
  erosion 
  of 
  the 
  river 
  bed 
  was 
  probably 
  very 
  slight, 
  that 
  of 
  the 
  

   banks 
  being 
  much 
  more 
  pronounced. 
  The 
  chief 
  part 
  in 
  the 
  

   cutting 
  of 
  the 
  gorge 
  was 
  enacted 
  by 
  the 
  cataract, 
  which 
  cut 
  

   backzvard 
  from 
  Lewiston, 
  the 
  amount 
  of 
  dozviiward 
  cutting 
  by 
  

   the 
  river 
  being 
  insignificant. 
  The 
  manner 
  in 
  which 
  the 
  cata- 
  

   ract 
  performed 
  its 
  work 
  of 
  cutting 
  may 
  today 
  be 
  observed 
  

   in 
  both 
  the 
  American 
  and 
  Canadian 
  falls, 
  a'^ 
  well 
  as 
  in 
  water- 
  

   falls 
  of 
  other 
  streams 
  falling 
  over 
  strata, 
  the 
  arrangement 
  of 
  which 
  

   is 
  similar 
  to 
  that 
  obtaining 
  at 
  Niagara. 
  The 
  essentials 
  are 
  a 
  re- 
  

   sistant 
  stratum 
  overlying 
  a 
  weak 
  one, 
  the 
  latter 
  being 
  constantly 
  

  

  