﻿178 
  E. 
  H. 
  Williams 
  — 
  Southern 
  Ice 
  Limit 
  in 
  Pennsylvania. 
  

  

  solid 
  glaciated 
  rock 
  in 
  the 
  Wyoming 
  valley 
  and 
  along 
  Penn's 
  

   creek 
  west 
  of 
  Lewisburg. 
  There 
  was 
  glacial 
  damming 
  in 
  the 
  

   valleys 
  of 
  the 
  Lehigh, 
  Lizard, 
  Mahoning, 
  and 
  Susquehanna 
  

   (main 
  and 
  north 
  branch) 
  up 
  to 
  600 
  feet 
  in 
  depth 
  ; 
  so 
  that 
  

   glacial 
  deposits 
  are 
  capped 
  by 
  varying 
  thicknesses 
  of 
  slack 
  

   water 
  clays, 
  and 
  flood 
  cones 
  were 
  formed 
  by 
  torrential 
  dis- 
  

   charges 
  into 
  the 
  emponded 
  waters 
  — 
  one 
  of 
  them 
  at 
  Jersey 
  

   Shore 
  being 
  over 
  a 
  mile 
  in 
  length, 
  1,000 
  feet 
  wide 
  and 
  170 
  feet 
  

   high 
  — 
  while 
  the 
  escaping 
  waters 
  distributed 
  gravels 
  over 
  high 
  

   cols 
  into 
  other 
  river 
  systems, 
  and 
  in 
  one 
  case 
  carried 
  them 
  to 
  

   within 
  75 
  miles 
  of 
  the 
  Potomac. 
  Some 
  points 
  require 
  more 
  

   extended 
  notice. 
  

  

  The 
  Schuylkill 
  gravels. 
  

  

  At 
  the 
  time 
  when 
  the 
  recent 
  State 
  geological 
  survey 
  was 
  

   made, 
  the 
  nature 
  of 
  glacial 
  gravels 
  was 
  not 
  so 
  well 
  understood 
  

   as 
  at 
  present, 
  and 
  the 
  reports 
  on 
  the 
  region 
  state 
  that 
  there 
  are 
  

   no 
  glacial 
  gravels 
  along 
  this 
  river. 
  There 
  are 
  no 
  striated 
  

   gravels 
  ; 
  but 
  extended 
  patches 
  of 
  unstratified 
  gravels 
  occur 
  at 
  

   all 
  points 
  along 
  the 
  Little 
  Schuylkill 
  and 
  the 
  main 
  stream, 
  and 
  

   the 
  writer 
  thinks 
  that 
  the 
  West 
  Philadelphia 
  gravels 
  may 
  be 
  

   partly 
  glacial, 
  as 
  Mr. 
  Salisbury 
  reports 
  finding 
  glaciated 
  stones 
  

   at 
  Norristown. 
  The 
  ice 
  covered 
  the 
  whole 
  of 
  the 
  extreme 
  end 
  

   of 
  the 
  southern 
  coal 
  field 
  from 
  Mauch 
  Chunk 
  to 
  Middleport 
  ; 
  

   so 
  that 
  the 
  upper 
  waters 
  of 
  the 
  Little 
  Schuylkill 
  in 
  the 
  

   Tamenend 
  valley 
  north 
  of 
  Tamaqua, 
  and 
  the 
  whole 
  valley 
  of 
  

   Panther 
  creek 
  drained 
  ice 
  covered 
  areas. 
  The 
  extension 
  west- 
  

   ward 
  in 
  the 
  Mahoning 
  valley 
  was 
  to 
  the 
  edge 
  of 
  the 
  col 
  

   between 
  Mahoning 
  creek 
  and 
  the 
  Little 
  Schuylkill, 
  so 
  that 
  

   some 
  of 
  the 
  glacial 
  waters 
  from 
  that 
  lobe 
  may 
  have 
  reached 
  

   the 
  latter 
  river 
  at 
  Zeiner's 
  Station. 
  Thence 
  down 
  the 
  river 
  to 
  

   Port 
  Clinton 
  the 
  gravels 
  are 
  irregularly 
  distributed 
  at 
  low 
  

   levels, 
  and 
  along 
  the 
  main 
  stream 
  south 
  of 
  the 
  Blue 
  Ridge. 
  

   About 
  half 
  way 
  between 
  Hamburg 
  and 
  Shoemakersville 
  the 
  

   upper 
  lobe 
  of 
  the 
  ice 
  from 
  the 
  Lehigh 
  region 
  reached 
  the 
  

   river 
  and 
  furnished 
  its 
  quota 
  of 
  trash, 
  and 
  at 
  Berkeley 
  the 
  

   lower 
  lobe 
  did 
  the 
  same. 
  The 
  new 
  Schuylkill 
  Valley 
  branch 
  

   of 
  the 
  Pennsylvania 
  P.P., 
  cuts 
  through 
  varying 
  thicknesses 
  of 
  

   unstratified 
  gravels, 
  and 
  especially 
  north 
  of 
  Douglassville. 
  

   The 
  contrast 
  between 
  the 
  deep 
  red 
  of 
  the 
  Trias 
  and 
  the 
  rusty 
  

   unstratified 
  cap 
  can 
  be 
  readily 
  seen 
  from 
  the 
  train. 
  The 
  highest 
  

   elevation 
  above 
  the 
  river 
  of 
  these 
  deposits 
  south 
  of 
  Reading, 
  

   thus 
  far, 
  has 
  been 
  30 
  feet. 
  

  

  The 
  Anthracite 
  regions. 
  

  

  With 
  the 
  exception 
  of 
  the 
  Southern 
  field, 
  west 
  of 
  Middle- 
  

   port, 
  and, 
  perhaps, 
  the 
  extreme 
  western 
  end 
  of 
  the 
  Western 
  

  

  