﻿Spencer 
  — 
  Origin 
  and 
  Age 
  of 
  the 
  Ontario 
  Shore-Line. 
  361 
  

  

  not 
  merely 
  that 
  drifting 
  along 
  the 
  shore, 
  but 
  also 
  that 
  washed 
  

   by 
  the 
  waves 
  from 
  greater 
  depths. 
  

  

  An 
  illustration 
  of 
  new-formed 
  land 
  is 
  seen 
  at 
  Atlantic 
  City, 
  

   where 
  groins 
  or 
  piers 
  were 
  built 
  outward 
  to 
  check 
  the 
  force 
  of 
  

   the 
  waves 
  encroaching 
  upon 
  the 
  coast. 
  But 
  the 
  groins 
  led 
  to 
  

   the 
  deposition 
  of 
  sand 
  between 
  them. 
  By 
  extending 
  these 
  

   and 
  adding 
  others 
  a 
  strip 
  of 
  new 
  land 
  was 
  acquired 
  in 
  40 
  years 
  

   for 
  a 
  length 
  of 
  three-fourths 
  of 
  a 
  mile, 
  with 
  breadth 
  reaching 
  

   to 
  one-fourth 
  of 
  a 
  mile, 
  curiously 
  leaving 
  the 
  lighthouse 
  in- 
  

   land. 
  

  

  During 
  high 
  water 
  of 
  1908, 
  the 
  lake 
  waves 
  washed 
  away 
  

   the 
  shore 
  road 
  around 
  Humber 
  Bay. 
  Here 
  also 
  protec- 
  

   tive 
  groins 
  were 
  built 
  (see 
  map, 
  tig. 
  1), 
  and 
  already 
  the 
  inter- 
  

   spaces 
  are 
  being 
  filled 
  with 
  beach 
  material. 
  

  

  Without 
  artificial 
  impediments, 
  a 
  barrier 
  beach 
  3 
  miles 
  long 
  

   was 
  formed 
  at 
  Asseagua 
  Light, 
  on 
  the 
  coast 
  of 
  Maryland, 
  in 
  

   40 
  years 
  ; 
  and 
  another 
  spit 
  or 
  barrier, 
  4,000 
  feet 
  long, 
  was 
  

   developed 
  on 
  the 
  western 
  side 
  of 
  Toronto 
  Harbour, 
  between 
  

   1841-1882 
  (see 
  b, 
  fig. 
  3) 
  and 
  now 
  completely 
  separates 
  the 
  

   bay 
  from 
  the 
  lake, 
  while 
  the 
  southern 
  side 
  of 
  the 
  beach 
  is 
  

   being 
  washed 
  away. 
  

  

  After 
  the 
  formation 
  of 
  the 
  gap 
  through 
  the 
  Toronto 
  barrier, 
  

   no 
  considerable 
  deposit 
  of 
  beach 
  material 
  from 
  the 
  east 
  was 
  

   carried 
  through 
  the 
  opening 
  into 
  the 
  quieter 
  waters 
  of 
  Toronto 
  

   Bay 
  ; 
  and 
  only 
  when 
  the 
  gap 
  was 
  artificially 
  closed 
  in 
  1883 
  

   and 
  further 
  obstructed 
  by 
  the 
  canal 
  piers, 
  did 
  the 
  sand 
  and 
  

   gravel 
  accumulate 
  here, 
  although 
  such 
  were 
  naturally 
  closing 
  

   the 
  western 
  end 
  of 
  the 
  harbour. 
  These 
  were 
  the 
  deposits 
  

   which 
  Prof. 
  Coleman 
  unfortunately 
  used 
  as 
  a 
  basis 
  for 
  his 
  

   speculations 
  of 
  geological 
  time. 
  The 
  above 
  examples 
  illustrate 
  

   the 
  effects 
  of 
  artificial 
  impediments 
  upon 
  wave 
  action 
  and 
  

   natural 
  changes 
  of 
  current, 
  showing 
  the 
  worthlessness 
  of 
  any 
  

   deductions 
  as 
  to 
  time 
  that 
  can 
  be 
  derived 
  from 
  them. 
  Further- 
  

   more 
  they 
  are 
  contrary 
  to 
  the 
  laws 
  of 
  mechanics. 
  Prof. 
  Cole- 
  

   man 
  also 
  failed 
  to 
  distinguish 
  the 
  underlying 
  clayey 
  sands 
  of 
  

   the 
  Don 
  delta 
  from 
  the 
  overlying 
  beach 
  materials 
  of 
  the 
  On- 
  

   tario 
  shore, 
  thereby 
  greatly 
  lengthening 
  his 
  conjectures 
  as 
  to 
  

   geological 
  time. 
  

  

  We 
  are 
  indebted 
  to 
  Prof. 
  Coleman 
  for 
  calling 
  our 
  attention 
  

   to 
  the 
  not-well-known 
  surveys 
  of 
  the 
  recession 
  of 
  Scarboro 
  

   bluffs, 
  which 
  had 
  been 
  made 
  for 
  the 
  Toronto 
  Water 
  Supply. 
  

   By 
  his 
  selection 
  of 
  the 
  figures, 
  rejecting 
  measurements 
  of 
  the 
  

   greater 
  erosion, 
  while 
  retaining 
  those 
  of 
  reduced 
  amount 
  

   (which 
  were 
  compensatory 
  in 
  the 
  variable 
  conditions), 
  he 
  

   assumes 
  1*62 
  feet 
  as 
  the 
  mean 
  rate 
  of 
  recession 
  in 
  place 
  of 
  2 
  

   feet 
  per 
  annum, 
  which 
  latter 
  is 
  the 
  mean 
  of 
  16 
  measurements 
  

   between 
  the 
  points 
  of 
  practically 
  no 
  encroachment. 
  

  

  