﻿REPORT 
  OF 
  THE 
  DIRECTOR 
  rl09 
  

  

  Fig. 
  30 
  

  

  Outline 
  of 
  the 
  typical 
  V-shaped 
  delta. 
  The 
  type 
  toward 
  which 
  the 
  deltas 
  forming 
  In 
  the 
  present 
  

   lakes 
  are 
  tending. 
  The 
  mainland 
  is 
  cross-hatched. 
  

  

  A 
  close 
  examination 
  of 
  the 
  deltas 
  marking 
  the 
  former 
  higher 
  lake 
  

   levels 
  indicate 
  an 
  almost 
  universal 
  tendency 
  toward 
  the 
  normally 
  

   formed 
  delta, 
  in 
  outline. 
  Their 
  forms 
  were 
  more 
  or 
  less 
  fan-like, 
  

   with 
  apex 
  toward 
  the 
  land 
  and 
  periphery 
  turned 
  lakeward. 
  In 
  

   marked 
  contrast 
  to 
  these, 
  is 
  the 
  type 
  of 
  deltas 
  in 
  some 
  cases 
  forming 
  

   in 
  the 
  present 
  lakes, 
  in 
  which 
  the 
  Y-shaped 
  outline, 
  or 
  the 
  " 
  delta 
  

   cusp" 
  "type, 
  is 
  strongly 
  exempliiied 
  — 
  with 
  apex 
  turned 
  lakeward 
  

   and 
  one 
  side 
  toward 
  the 
  land. 
  The 
  apices 
  of 
  some 
  point 
  directly 
  

   Jakeward, 
  of 
  others 
  southward, 
  giving 
  an 
  intermediate 
  form 
  and 
  

   indicating 
  a 
  prevailing 
  current 
  in 
  that 
  direction. 
  

  

  The 
  difference 
  in 
  the 
  two 
  classes 
  of 
  deltas, 
  as 
  above 
  distinguished, 
  

   can 
  probably 
  be 
  accounted 
  for, 
  mainly, 
  upon 
  the 
  ground 
  of 
  age 
  and 
  

   the 
  conditions 
  prevailing 
  for 
  the 
  two 
  periods 
  of 
  delta 
  formation, 
  

   which 
  must 
  have 
  been 
  of 
  an 
  opposite 
  nature. 
  

  

  Differential 
  movement 
  in 
  the 
  Finger-lake 
  region 
  

  

  No 
  perfectly 
  reliable 
  results 
  could 
  be 
  obtained 
  for 
  the 
  differential 
  

   uplift 
  in 
  this 
  region, 
  since 
  the 
  desertion 
  of 
  the 
  shore 
  lines 
  by 
  the 
  

   static 
  waters. 
  While 
  the 
  terraces 
  show 
  a 
  fairly 
  good 
  correlation 
  

   they 
  most 
  certainly 
  reveal 
  some 
  of 
  the 
  conditions 
  under 
  w^hich 
  they 
  

   were 
  constructed, 
  such 
  as, 
  extreme 
  variableness 
  in 
  the 
  stream 
  grades, 
  

  

  a 
  For 
  the 
  different 
  ways 
  in 
  which 
  "delta 
  cusps 
  " 
  may 
  be 
  formed, 
  see, 
  

   Gulliver, 
  F. 
  P., 
  Cuspate 
  forelands. 
  

  

  Bull. 
  geol. 
  soc. 
  Am., 
  1895, 
  7, 
  399-122 
  : 
  specially 
  417-21. 
  

  

  