﻿GEOLOGY 
  OF 
  THE 
  PORT 
  LEYDEN 
  QUADRANGLE 
  43 
  

  

  thickness 
  just 
  west 
  of 
  Port 
  Leyden 
  is 
  only 
  500 
  feet. 
  Between 
  these 
  

   places, 
  which 
  are 
  39 
  miles 
  apart, 
  the 
  thickness 
  has 
  diminished 
  400 
  

   feet 
  or 
  at 
  the 
  rate 
  of 
  over 
  10 
  feet 
  per 
  mile 
  toward 
  the 
  east. 
  

  

  At 
  Central 
  Square 
  it 
  is 
  806 
  feet 
  from 
  t'he 
  top 
  of 
  the 
  Trenton 
  to 
  

   the 
  Precambric, 
  while 
  at 
  Port 
  Leyden 
  it 
  is 
  500 
  feet. 
  Thus 
  in 
  a 
  

   distance 
  of 
  45 
  miles 
  the 
  thickness 
  has 
  diminished 
  306 
  feet 
  or 
  at 
  the 
  

   rate 
  of 
  nearly 
  7 
  feet 
  per 
  mile 
  toward 
  the 
  northeast. 
  

  

  In 
  the 
  Stillwater 
  well 
  the 
  top 
  of 
  the 
  Trenton 
  lies 
  772 
  feet 
  abovv- 
  

   the 
  Precambric, 
  while 
  at 
  Martinsburg 
  it 
  is 
  about 
  600 
  feet. 
  Thi^ 
  

   shows 
  a 
  decreased 
  thickness 
  in 
  27 
  miles 
  of 
  172 
  feet 
  or 
  at 
  the 
  rate 
  of 
  

   over 
  6 
  feet 
  per 
  mile 
  toward 
  the 
  northeast. 
  

  

  Thus 
  we 
  see 
  that 
  there 
  is 
  an 
  increasing 
  thickness 
  of 
  these 
  forma- 
  

   tions 
  toward 
  the 
  southwest 
  and 
  west 
  at 
  from 
  6 
  to 
  10 
  feet 
  per 
  mile, 
  

   and 
  these 
  figures 
  may, 
  in 
  a 
  general 
  way 
  at 
  least, 
  be 
  taken 
  to 
  indicate 
  

   the 
  slope 
  of 
  the 
  surface 
  upon 
  which 
  the 
  Paleozoic 
  deposits 
  were 
  be- 
  

   ing 
  laid 
  down. 
  

  

  These 
  results 
  are 
  significant 
  when 
  compared 
  with 
  the 
  results 
  

   similarly 
  obtained 
  by 
  Gushing 
  for 
  the 
  Little 
  Falls 
  district 
  and 
  by 
  the 
  

   writer 
  for 
  the 
  Remsen 
  quadrangle. 
  In 
  the 
  Little 
  Falls 
  region 
  the 
  

   slope 
  receiving 
  Beekmantown 
  deposition 
  was 
  about 
  30 
  feet 
  per 
  mile 
  

   southward 
  ; 
  while 
  in 
  the 
  Remsen 
  district 
  the 
  slope 
  receiving 
  Trenton 
  

   deposition 
  was 
  from 
  6 
  to 
  20 
  feet 
  per 
  mile 
  southwestward, 
  the 
  great- 
  

   est 
  slope 
  being 
  in 
  the 
  southeastern 
  portion 
  of 
  the 
  district. 
  Thus 
  it 
  

   is 
  pretty 
  well 
  established 
  that 
  the 
  slope 
  of 
  the 
  surface 
  receiving 
  

   Paleozoic 
  deposition 
  was 
  very 
  considerably 
  greater 
  in 
  the 
  vicinity 
  of 
  

   Little 
  Falls 
  than 
  in 
  the 
  vicinity 
  of 
  Port 
  Leyden 
  and 
  that 
  there 
  was 
  a 
  

   gradual 
  change 
  from 
  the 
  steeper 
  to 
  the 
  more 
  nearly 
  level 
  surface. 
  

  

  The 
  results 
  obtained 
  for 
  the 
  Port 
  Leyden 
  quadrangle 
  are 
  also 
  

   significant 
  in 
  another 
  way. 
  The 
  thickness 
  of 
  the 
  formations 
  here, 
  

   from 
  the 
  top 
  of 
  the 
  Lorraine 
  to 
  the 
  Precambric, 
  is 
  approximately 
  

   1400 
  feet. 
  This 
  thickness 
  is 
  great 
  enough 
  so 
  that 
  even 
  after 
  allow- 
  

   ing 
  for 
  decreased 
  thickness 
  due 
  to 
  overlap 
  and 
  a 
  possibly 
  increased 
  

   slo'pe 
  (receiving 
  sediments) 
  as 
  the 
  heart 
  of 
  the 
  Adirondacks 
  wa- 
  

   approached, 
  we 
  seem 
  to 
  have 
  here 
  a 
  strong 
  argument 
  in 
  favor 
  of 
  the 
  

   submergence 
  of 
  the 
  region 
  for 
  many 
  miles 
  to 
  the 
  east 
  and 
  north- 
  

   east 
  of 
  Port 
  Leyden, 
  so 
  that 
  by 
  the 
  close 
  of 
  the 
  Lower 
  Siluric 
  the 
  

   submergence 
  extended 
  to, 
  or 
  close 
  to, 
  the 
  heart 
  of 
  the 
  Adirondack?. 
  

   This 
  conclusion 
  is 
  quite 
  different 
  from 
  that 
  reached 
  by 
  Gushing 
  by 
  

   similar 
  reasoning 
  for 
  the 
  southern 
  Adirondacks. 
  He 
  says 
  :^ 
  " 
  This 
  

   line 
  of 
  evidence 
  would 
  therefore, 
  so 
  far 
  as 
  it 
  may 
  be 
  worth 
  anything, 
  

  

  1 
  N. 
  Y. 
  State 
  Mus. 
  Biil. 
  ']']. 
  1905. 
  p. 
  61-62. 
  

  

  