﻿FIFTH 
  REPORT 
  OF 
  THE 
  DIRECTOR 
  I908 
  II 
  

  

  assembled 
  a 
  body 
  of 
  data 
  of 
  extraordinary 
  importance 
  bearing 
  upon 
  

   the 
  physiography 
  and 
  geological 
  structure 
  of 
  the 
  lower 
  Hudson 
  

   valley 
  and 
  the 
  adjoining 
  region. 
  Two 
  years 
  ago 
  the 
  areal 
  survey 
  

   of 
  the 
  Highlands 
  quadrangles 
  was 
  placed 
  in 
  charge 
  of 
  Dr 
  Charles 
  

   P. 
  Berkey 
  who 
  has 
  also 
  become 
  associated 
  as 
  geologist 
  with 
  the 
  

   Board 
  of 
  Water 
  Supply. 
  This 
  double 
  professional 
  interest 
  en- 
  

   ables 
  Dr 
  Berkey 
  to 
  assemble 
  and 
  combine 
  all 
  the 
  data 
  most 
  effect- 
  

   ively. 
  During 
  the 
  past 
  season 
  more 
  time 
  was 
  spent 
  upon 
  struc- 
  

   tural 
  and 
  petrogi'aphic 
  details 
  of 
  this 
  work 
  than 
  on 
  a 
  continuance 
  

   of 
  areal 
  mapping, 
  as 
  this 
  was 
  made 
  necessary 
  from 
  the 
  accumu- 
  

   lation 
  of 
  drill 
  records 
  and 
  similar 
  data. 
  It 
  is 
  of 
  interest 
  to 
  note 
  

   that 
  these 
  deep 
  seated 
  data 
  do 
  not 
  intimate 
  any 
  inaccuracy 
  in 
  the 
  

   determination 
  from 
  the 
  surface, 
  of 
  the 
  stratigraphic 
  succession 
  or 
  

   of 
  general 
  interpretation. 
  On 
  the 
  contrary 
  these 
  well 
  established 
  

   factors 
  were 
  a 
  constant 
  guide 
  to 
  the 
  engineering 
  exploration 
  and 
  

   to 
  the 
  interpretation 
  of 
  data 
  gathered 
  throughout 
  the 
  work. 
  But 
  

   the 
  data 
  available 
  are 
  so 
  abundant 
  and 
  well 
  distributed 
  as 
  to 
  enable 
  

   the 
  construction 
  of 
  cross 
  sections 
  with 
  exceptional 
  accuracy. 
  The 
  

   preliminary 
  explorations 
  of 
  the 
  Catskill 
  Aqueduct 
  are 
  largely 
  

   finished. 
  More 
  complete 
  data, 
  such 
  as 
  may 
  be 
  gathered 
  as 
  the 
  

   tunnels 
  progress 
  will 
  not 
  be 
  obtainable 
  for 
  several 
  years 
  and 
  it 
  

   therefore 
  seems 
  advisable 
  to 
  arrange 
  the 
  present 
  matter 
  for 
  imme- 
  

   diate 
  use. 
  This 
  is 
  being 
  done 
  in 
  the 
  form 
  of 
  a 
  bulletin 
  which 
  

   will 
  present 
  an 
  outline 
  of 
  the 
  geologv^ 
  of 
  southeaste'rn 
  New 
  York 
  as 
  

   now 
  understood, 
  and 
  a 
  discussion 
  of 
  the 
  significance 
  of 
  the 
  newer 
  

   factors. 
  

  

  In 
  further 
  areal 
  work 
  in 
  the 
  Highlands 
  additional 
  limestone 
  

   occurrences 
  have 
  been 
  noted 
  some 
  of 
  which 
  at 
  least 
  are 
  clearly 
  

   interbedded 
  or 
  included 
  in 
  the 
  gneisses. 
  These 
  interbedded 
  lime- 
  

   stones 
  (probably 
  of 
  Grenville 
  age) 
  are 
  now 
  known 
  in 
  the 
  High- 
  

   lands 
  proper 
  at 
  occasional 
  points 
  from 
  the 
  vicinity 
  of 
  Brewster 
  

   near 
  the 
  Connecticut 
  line 
  to 
  Tuxedo 
  lake 
  near 
  the 
  New 
  Jersey 
  

   line, 
  but 
  they 
  appear 
  to 
  be 
  most 
  frequent 
  in 
  the 
  central 
  or 
  Hudson 
  

   River 
  belt. 
  An 
  important 
  connecting 
  link 
  between 
  the 
  gneisses 
  of 
  

   New 
  York 
  city 
  and 
  of 
  the 
  Highlands 
  proper 
  was 
  found 
  in 
  the 
  

   discovery 
  of 
  interbedded 
  limestones 
  in 
  the 
  city 
  at 
  the 
  type 
  locality 
  

   of 
  the 
  Fordham 
  gneiss. 
  Three 
  points 
  were 
  found 
  near 
  Jerome 
  

   Park 
  reservoir 
  in 
  the 
  Borough 
  of 
  the 
  Bronx 
  where 
  the 
  limestones 
  

   are 
  surely 
  of 
  this 
  interbedded 
  relation. 
  In 
  two 
  of 
  them 
  the 
  struct- 
  

   ural 
  relations 
  are 
  unusually 
  clear. 
  They 
  are 
  small 
  beds 
  but 
  lie 
  

   within 
  small 
  anticlinal 
  folds 
  in 
  such 
  a 
  way 
  as 
  wholly 
  to 
  preclude 
  

   the 
  possibility 
  of 
  infolding 
  of 
  overlying 
  strata. 
  In 
  all 
  cases 
  these 
  

  

  