﻿Appalachian 
  Geosyncline. 
  • 
  445 
  

  

  feet, 
  Montrose 
  red 
  shale 
  2000 
  feet, 
  Delaware 
  flags 
  1200 
  feet, 
  

   New 
  Milford 
  red 
  and 
  gray 
  shales 
  and 
  sandstones 
  700 
  feet, 
  

   Starucca 
  flags 
  600 
  feet 
  ; 
  total, 
  7544 
  feet 
  for 
  the 
  Lehigh 
  River 
  

   section. 
  

  

  In 
  1882 
  Mr. 
  Arthur 
  Winslow 
  measured 
  sections 
  in 
  detail 
  

   from 
  Wilkes-Barre 
  to 
  the 
  Lehigh 
  Gap. 
  His 
  section 
  of 
  the 
  

   Catskill 
  on 
  the 
  Lehigh. 
  River* 
  shows 
  no 
  such 
  division 
  of 
  the 
  

   Catskill 
  into 
  distinct 
  groups 
  and 
  the 
  character 
  of 
  his 
  section 
  

   corresponds 
  much 
  more 
  with 
  the 
  one 
  given 
  in 
  this 
  paper 
  for 
  

   Schuylkill 
  County. 
  Winslow's 
  section 
  and 
  White's 
  observa- 
  

   tions 
  on 
  the 
  changeable 
  character 
  of 
  the 
  Catskill 
  in 
  the 
  Sus- 
  

   quehanna 
  River 
  regionf 
  point 
  to 
  the 
  error 
  likely 
  to 
  be 
  in- 
  

   volved 
  in 
  such 
  attempted 
  correlations 
  as 
  those 
  of 
  Lesley's 
  and 
  

   mark 
  out 
  the 
  Catskill 
  as 
  a 
  formation 
  particularly 
  subject 
  to 
  

   lateral 
  variation 
  of 
  its 
  members. 
  Inconstancy 
  of 
  sedimenta- 
  

   tion 
  was 
  the 
  rule 
  and 
  is 
  doubtless 
  of 
  significance 
  in 
  connection 
  

   with 
  its 
  mode 
  of 
  origin. 
  

  

  Measurements 
  of 
  the 
  Catskill 
  by 
  different 
  observers 
  and 
  in 
  

   different 
  regions 
  cannot 
  well 
  be 
  compared 
  becanse 
  both 
  the 
  

   lower 
  and 
  upper 
  limits 
  are 
  indefinite, 
  the 
  Catskill 
  grading 
  into 
  

   the 
  adjacent 
  formations 
  by 
  beds 
  of 
  passage. 
  Below, 
  on 
  the 
  east 
  

   it 
  has 
  not 
  been 
  separated 
  in 
  northeastern 
  Pennsylvania 
  from 
  the 
  

   Oneonta 
  and 
  on 
  the 
  west 
  its' 
  base 
  is 
  commonly 
  taken 
  as 
  the 
  

   lowest 
  prominent 
  red 
  bed. 
  But 
  this 
  horizon 
  varies 
  in 
  nearby 
  

   localities. 
  On 
  the 
  upper 
  limit 
  the 
  separation 
  from 
  the 
  Pocono 
  

   sandstones 
  and 
  conglomerates 
  is 
  arbitrary 
  and 
  the 
  Pennsylvania 
  

   geologists 
  have 
  differed 
  among 
  themselves 
  as 
  to 
  the 
  boundary 
  

   to 
  the 
  extent 
  of 
  several 
  hundred 
  feet. 
  The 
  top 
  of 
  the 
  last 
  

   important 
  red 
  shale 
  has 
  usually 
  been 
  chosen 
  as 
  the 
  dividing 
  

   plane. 
  An 
  idea 
  of 
  the 
  great 
  volume 
  of 
  this 
  formation 
  may 
  be 
  

   obtained 
  by 
  noting 
  that 
  in 
  the 
  Catskill 
  mountains 
  the 
  portion 
  

   spared 
  by 
  erosion 
  has 
  a 
  thickness 
  of 
  about 
  3,000 
  feet; 
  or 
  4,000 
  

   feet 
  if 
  the 
  Oneonta 
  be 
  included. 
  The 
  base 
  rises 
  stratigraphi- 
  

   cally 
  on 
  going 
  southwest, 
  but 
  the 
  Catskill 
  and 
  so 
  much 
  of 
  the 
  

   Oneonta 
  as 
  is 
  represented 
  increase 
  nevertheless 
  to 
  a 
  thickness 
  

   of 
  7,500 
  feet 
  on 
  the 
  Lehigh 
  River 
  in 
  Pennsylvania.^ 
  On 
  the 
  

   southern 
  boundary 
  of 
  Pennsylvania, 
  in 
  Fulton 
  County, 
  the 
  Cats- 
  

   kill 
  is 
  given 
  a 
  thickness 
  of 
  about 
  4,000 
  feet. 
  From 
  these 
  large 
  

   figures 
  for 
  the 
  eastern 
  outcrops 
  the 
  thickness 
  rapidly 
  diminishes 
  

   westward, 
  the 
  formation 
  disappearing 
  in 
  western 
  New 
  York 
  

   and 
  Pennsylvania. 
  

  

  In 
  the 
  region 
  of 
  the 
  New 
  York 
  and 
  Pennsylvania 
  boundaries 
  

   west 
  of 
  the 
  seventy-eighth 
  meridian, 
  the 
  deposition 
  of 
  red 
  shale 
  

   continued 
  into 
  the 
  basal 
  Mississippian 
  as 
  shown 
  by 
  marine 
  fos- 
  

  

  * 
  Ann. 
  Eept. 
  for 
  1886, 
  pt. 
  iv, 
  pp. 
  1363, 
  1364, 
  1887. 
  Summary 
  finai 
  report, 
  

   ii, 
  pp. 
  1594-1596, 
  1892. 
  

  

  fSec. 
  Geol. 
  Surv. 
  Pa., 
  vol. 
  G-7, 
  p. 
  55, 
  1883. 
  

  

  XI. 
  C. 
  White. 
  Second 
  Geol. 
  Surv. 
  of 
  Pa., 
  vol. 
  G-6, 
  pp. 
  77, 
  78, 
  1882. 
  

  

  Am. 
  Jour. 
  Sci.— 
  Fourth 
  Series, 
  Vol. 
  XXXVI, 
  No. 
  215. 
  — 
  November, 
  1913. 
  

   30 
  

  

  