﻿GEOLOGY 
  OF 
  THE 
  PORT 
  LEYDEN 
  QUADRANGLE 
  5 
  1 
  

  

  and 
  limestone 
  are 
  also 
  present 
  in 
  great 
  abundance 
  in 
  the 
  till 
  and 
  

   other 
  drift 
  of 
  the 
  Remsen 
  quadrangle. 
  However, 
  much 
  of 
  the 
  shale 
  

   must 
  have 
  been 
  ground 
  up 
  and 
  carried 
  away 
  by 
  glacial 
  waters. 
  

  

  Glacial 
  sand 
  plains 
  or 
  terraces 
  

  

  A 
  remarkable 
  development 
  of 
  glacial 
  sand 
  plains 
  or 
  terraces 
  is 
  

   to 
  be 
  found 
  within 
  the 
  Port 
  Leyden 
  quadrangle. 
  Here, 
  on 
  the 
  east 
  

   side 
  of 
  the 
  river, 
  most 
  of 
  the 
  region 
  is 
  occupied 
  by 
  these 
  terraces, 
  

   which 
  taken 
  together 
  may 
  be 
  looked 
  upon 
  as 
  a 
  single 
  great 
  terrace 
  

   with 
  steep 
  front 
  facing 
  Black 
  river 
  [see 
  fig. 
  5]. 
  On 
  the 
  Port 
  Ley- 
  

   den 
  sheet 
  alone 
  they 
  cover 
  fully 
  75 
  square 
  miles 
  and 
  continue 
  both 
  

   northward 
  and 
  southward 
  from 
  this 
  area. 
  They 
  are 
  clearly 
  shown 
  

   upon 
  the 
  topographic 
  map. 
  The 
  sands 
  and 
  gravels 
  of 
  these 
  terraces 
  

   show 
  a 
  depth 
  of 
  from 
  200 
  to 
  250 
  feet 
  along 
  the 
  western 
  edge, 
  and 
  

   there 
  is 
  a 
  gradual 
  thinning 
  out 
  to 
  disappearance 
  several 
  miles 
  east- 
  

   ward. 
  

  

  Except 
  in 
  a 
  few 
  cases 
  the 
  flat-topped 
  surfaces 
  are 
  practically 
  desti- 
  

   tute 
  of 
  large 
  boulders. 
  A 
  characteristic 
  feature 
  is 
  the 
  presence 
  of 
  

   pitlike 
  or 
  kettlelike 
  depressions 
  over 
  the 
  surfaces 
  [see 
  map]. 
  These 
  

   depressions 
  are 
  of 
  various 
  sizes 
  and 
  shapes 
  and 
  are 
  sometimes 
  occu- 
  

   pied 
  by 
  lakes 
  or 
  ponds, 
  as 
  for 
  example 
  Brantingham, 
  Little 
  Otter 
  

   and 
  Catspaw 
  lakes 
  and 
  Sand 
  pond. 
  They 
  are 
  often 
  very 
  steep- 
  

   sided 
  and 
  range 
  in 
  depth 
  from 
  a 
  few 
  feet 
  to 
  50 
  or 
  60 
  feet. 
  The 
  

   terraces 
  are 
  dissected 
  by 
  many 
  streams 
  so 
  that 
  enough 
  good 
  sections 
  

   are 
  exposed 
  to 
  make 
  it 
  certain 
  that 
  the 
  materials 
  are 
  crudely 
  strati- 
  

   fied 
  and 
  cross-bedded, 
  and 
  occasionally 
  interstratified 
  with 
  clay, 
  thus 
  

   proving 
  that 
  they 
  were 
  water 
  laid. 
  The 
  western 
  margin 
  of 
  this 
  

   great 
  terrace 
  is 
  distinctly 
  lobate 
  in 
  character 
  and 
  is 
  strongly 
  sug- 
  

   gestive 
  of 
  delta 
  origin 
  as 
  for 
  example 
  in 
  the 
  southeastern 
  part 
  of 
  

   the 
  quadrangle. 
  Another 
  very 
  notable 
  feature 
  is 
  the 
  concordance 
  

   of 
  altitudes 
  at 
  about 
  the 
  same 
  distance 
  back 
  from 
  the 
  margin. 
  The 
  

   altitudes 
  vary 
  from 
  about 
  11 
  50 
  to 
  1260 
  feet, 
  the 
  higher 
  altitude> 
  

   being 
  on 
  the 
  east, 
  thus 
  giving 
  a 
  gradual 
  slope 
  of 
  the 
  terrace 
  surface 
  

   toward 
  Black 
  river. 
  

  

  A 
  study 
  of 
  the 
  character 
  and 
  distribution 
  of 
  these 
  terraces 
  as 
  well 
  

   as 
  their 
  relation 
  to 
  the 
  other 
  drift 
  deposits, 
  leaves 
  no 
  doubt 
  as 
  to 
  

   their 
  origin 
  as 
  delta 
  deposits 
  in 
  a 
  marginal 
  lake 
  along 
  the 
  waning 
  ice 
  

   tongue 
  during 
  its 
  retreat 
  from 
  the 
  Black 
  river 
  valley. 
  The 
  im- 
  

   mense 
  amount 
  of 
  material 
  thus 
  deposited 
  was 
  readily 
  obtained 
  by 
  

   the 
  streams, 
  especially 
  Black 
  and 
  Moose 
  rivers 
  and 
  Otter 
  creek, 
  as 
  

   they 
  emerged 
  from 
  the 
  newly 
  drift-strewn 
  Adirondack 
  highlands. 
  

  

  