﻿Reelevation 
  of 
  the 
  St. 
  Lawrence 
  river 
  basin. 
  11 
  

  

  Lake 
  Lroquois* 
  — 
  This 
  glacial 
  lake, 
  outflowing 
  at 
  Rome 
  to 
  

   the 
  Mohawk 
  and 
  Hudson, 
  occupied 
  less 
  area 
  in 
  the 
  west 
  part 
  

   of 
  the 
  Lake 
  Ontario 
  basin 
  during 
  its 
  earliest 
  stage 
  than 
  during 
  

   the 
  later 
  and 
  probably 
  longer 
  enduring 
  lake 
  stage 
  by 
  which 
  

   the 
  high 
  Iroquois 
  beach 
  in 
  that 
  region 
  was 
  formed. 
  Previous 
  

   to 
  the 
  date 
  of 
  the 
  western 
  development 
  of 
  the 
  Iroquois 
  beach, 
  

   the 
  early 
  water 
  level 
  stood 
  at 
  one 
  time 
  only 
  a 
  little 
  higher 
  than 
  

   the 
  present 
  Lake 
  Ontario 
  at 
  Toronto 
  and 
  Scarboro 
  Heights, 
  6 
  

   to 
  15 
  miles 
  east 
  of 
  Toronto, 
  as 
  compared 
  with 
  the 
  altitude, 
  

   doubtless 
  absolutely 
  lower 
  than 
  now 
  with 
  regard 
  to 
  the 
  sea, 
  

   which 
  the 
  land 
  then 
  held 
  in 
  that 
  part 
  of 
  the 
  lake 
  basin. 
  This 
  

   is 
  shown 
  by 
  the 
  occurrence 
  of 
  fossil 
  fresh-water 
  mollusks 
  of 
  

   lourteen 
  species, 
  and 
  wood 
  of 
  ash, 
  oak, 
  and 
  American 
  yew, 
  in 
  

   beds 
  at 
  Toronto, 
  described 
  by 
  Coleman, 
  which 
  now 
  are 
  33 
  to 
  

   51 
  feet 
  above 
  Lake 
  Ontario, 
  or 
  280 
  to 
  298 
  feet 
  above 
  the 
  sea. 
  

   All 
  the 
  mollusk 
  species 
  are 
  now 
  living; 
  but 
  four 
  are 
  restricted, 
  

   so 
  far 
  as 
  known, 
  to 
  waters 
  tributary 
  to 
  the 
  Mississippi. 
  A 
  

   boulder-bearing 
  surface 
  deposit 
  above 
  these 
  beds 
  proves 
  that 
  

   the 
  front 
  of 
  the 
  ice-sheet 
  was 
  not 
  far 
  distant 
  ; 
  but 
  the 
  climatic 
  

   conditions 
  of 
  that 
  time, 
  clearly 
  indicated 
  by 
  the 
  fauna 
  and 
  

   flora, 
  were 
  as 
  mild 
  as 
  now. 
  There 
  next 
  ensued, 
  probably, 
  a 
  

   gradual 
  rise 
  of 
  the 
  lake, 
  due 
  to 
  an 
  uplifting 
  of 
  the 
  country 
  

   about 
  its 
  outlet 
  at 
  Rome, 
  until 
  it 
  stood 
  at 
  the 
  level 
  of 
  the 
  well 
  

   defined 
  Iroquois 
  beach, 
  which 
  has 
  a 
  height 
  at 
  Toronto 
  of 
  

   about 
  200 
  feet 
  above 
  Lake 
  Ontario. 
  Thick 
  fossiliferous 
  delta 
  

   deposits 
  had 
  been, 
  meanwhile, 
  brought 
  into 
  the 
  north 
  edge 
  of 
  

   the 
  lake 
  at 
  Toronto 
  and 
  several 
  miles 
  eastward 
  along 
  the 
  lake- 
  

   cliif 
  section 
  of 
  Scarboro 
  Heights, 
  described 
  by 
  Hinde 
  ; 
  and 
  re- 
  

   peated 
  re-advances 
  of 
  the 
  ice-front, 
  one 
  during, 
  and 
  another 
  

   after, 
  the 
  delta 
  accumulation, 
  formed, 
  at 
  the 
  locality 
  last 
  noted, 
  

   two 
  deposits 
  of 
  till 
  or 
  boulder-clay. 
  

  

  In 
  a 
  limited 
  sense 
  the 
  Toronto 
  and 
  Scarboro 
  fossils 
  may 
  be 
  

   called 
  Interglacial, 
  since 
  they 
  lie 
  between 
  deposits 
  of 
  glacial 
  

   drift 
  ; 
  but 
  they 
  seem 
  better 
  referred 
  to 
  moderate 
  oscillations 
  

   of 
  the 
  ice 
  boundary 
  than 
  to 
  the 
  distinct 
  glacial 
  epochs 
  which 
  

   Coleman 
  and 
  Hinde 
  infer 
  from 
  them. 
  Both 
  these 
  beds 
  and 
  

  

  * 
  J. 
  W. 
  Spencer, 
  "The 
  Deformation 
  of 
  the 
  Iroquois 
  Beach 
  and 
  Birth 
  of 
  Lake 
  

   Ontario," 
  this 
  Journal. 
  Ill, 
  vol. 
  xl, 
  pp. 
  443-451, 
  with 
  map, 
  Dec, 
  1890 
  ; 
  and 
  

   papers 
  previously 
  cited. 
  Thomas 
  Roy 
  (in 
  paper 
  by 
  Sir 
  Charles 
  Lyell), 
  Proceed- 
  

   ings 
  Geol. 
  Soc, 
  London, 
  vol. 
  ii. 
  1837, 
  pp. 
  537, 
  538. 
  Sir 
  Charles 
  Lyell, 
  Travels 
  in 
  

   N. 
  A., 
  in 
  1841-42. 
  vol. 
  ii, 
  chapter 
  xx. 
  E. 
  J. 
  Chapman, 
  Canadian 
  Journal, 
  new 
  

   series, 
  vol. 
  vi, 
  1861, 
  pp. 
  221-22y, 
  and 
  497, 
  498. 
  Sand 
  ford 
  Fleming, 
  Can. 
  Jour., 
  

   same 
  vol. 
  vi. 
  pp. 
  247-253. 
  GTeorge 
  J. 
  Hinde, 
  Can. 
  Jour., 
  vol. 
  xv, 
  1877. 
  pp. 
  388- 
  

   413. 
  A. 
  P. 
  Coleman, 
  Am. 
  Geologist, 
  vol. 
  xiii, 
  pp. 
  85-95, 
  Feb. 
  1894. 
  Geol. 
  Sur- 
  

   vey 
  of 
  Canada, 
  Report 
  of 
  Progress 
  to 
  1863, 
  pp. 
  912, 
  913. 
  James 
  Hall, 
  Geology 
  

   of 
  New 
  York. 
  Partiv, 
  1843, 
  pp. 
  348-351. 
  Baron 
  Gerard 
  de 
  Geer, 
  "On 
  Pleistocene 
  

   Changes 
  of 
  Level 
  in 
  eastern 
  North 
  America." 
  Proc. 
  Boston 
  Soc. 
  Nat. 
  Hist., 
  vol. 
  

   xxv, 
  1892, 
  pp. 
  454-477, 
  with 
  map; 
  also 
  (excepting 
  the 
  map) 
  in 
  Am. 
  Geologist, 
  

   vol. 
  xi, 
  pp. 
  22-44, 
  Jan., 
  1893. 
  G. 
  K. 
  Gilbert, 
  F. 
  B. 
  Taylor, 
  B. 
  W. 
  Claypole, 
  G. 
  

   F. 
  Wright, 
  and 
  Warren 
  Upham, 
  as 
  cited 
  for 
  Lakes 
  Warren 
  and 
  Algonquin. 
  

  

  