﻿12 
  NEW 
  YORK 
  STATE 
  MUSEUM 
  

  

  oldest 
  limestones 
  are 
  very 
  impure. 
  At 
  Jerome 
  Park 
  reservoir 
  they 
  

   carry 
  an 
  abundance 
  . 
  of 
  chondrodite 
  and 
  many 
  unusual 
  minerals, 
  

   such 
  as 
  actinolite, 
  sphalerite 
  and 
  galenite. 
  

  

  It 
  is 
  fairly 
  certain 
  that 
  the 
  gneiss 
  series 
  in 
  southwestern 
  New 
  

   York 
  can 
  best 
  be 
  regarded 
  as 
  a 
  unit 
  formation, 
  the 
  basis 
  of 
  which 
  

   is 
  a 
  metamorphosed 
  sediment 
  into 
  which 
  are 
  intruded 
  in 
  a 
  highly 
  

   complex 
  manner 
  igneous 
  masses 
  of 
  various 
  kinds 
  and 
  sometimes 
  of 
  

   so 
  large 
  amount 
  as 
  to 
  wholly 
  obscure 
  the 
  original 
  type. 
  In 
  some 
  

   localities 
  these 
  igneous 
  masses 
  largely 
  predominate 
  and 
  may 
  merit 
  

   local 
  names 
  but 
  in 
  all 
  cases 
  seen 
  they 
  give 
  evidence 
  of 
  being 
  

   distinctly 
  younger 
  than 
  the 
  associated 
  recrystallized 
  sediments. 
  

  

  An 
  additional 
  complexity 
  has 
  been 
  observed 
  in 
  the 
  vicinity 
  of 
  

   Brewster 
  in 
  the 
  Carmel 
  quadrangle 
  on 
  the 
  southeast 
  margin 
  of 
  

   the 
  Highlands. 
  Several 
  narrow 
  but 
  remarkably 
  continuous 
  strips 
  

   of 
  limestone 
  occur 
  in 
  the 
  schist. 
  The 
  m.ost 
  reasonable 
  explanation 
  

   of 
  them 
  is 
  that 
  they 
  are 
  interbedded 
  with 
  the 
  Manhattan 
  schist. 
  All 
  

   of 
  the 
  crystahine 
  formations 
  have 
  been 
  traced 
  to 
  the 
  State 
  line 
  in 
  

   this 
  vicinity, 
  crossing 
  the 
  border 
  into 
  both 
  Danbury 
  and 
  Ridge- 
  

   field, 
  Conn. 
  In 
  comparing 
  the 
  formations 
  of 
  the 
  New 
  York 
  side, 
  

   which 
  have 
  been 
  followed 
  in 
  this 
  investigation 
  continuously 
  from 
  

   their 
  type 
  localities 
  in 
  New 
  York 
  city, 
  with 
  the 
  new 
  (1906) 
  areal 
  

   geologic 
  map 
  of 
  Connecticut, 
  the 
  following 
  points 
  of 
  correlation 
  

   are 
  estabhshed: 
  

  

  1 
  Two 
  belts 
  of 
  crystalline 
  limestone 
  known 
  on 
  the 
  New 
  York 
  

   side 
  as 
  Inwood 
  limestone 
  continue 
  into 
  Connecticut, 
  the 
  one 
  into 
  

   Danbury 
  and 
  the 
  other 
  into 
  Ridgefield, 
  as 
  '' 
  Stockbridge 
  " 
  lime- 
  

   stone. 
  

  

  2 
  Two 
  belts 
  of 
  older 
  gneisses, 
  considered 
  on 
  the 
  New 
  York 
  

   side 
  as 
  equivalent 
  to 
  the 
  Fordham 
  gneiss, 
  continue 
  into 
  Connecticut 
  

   as 
  the 
  '' 
  Becket 
  " 
  gneiss. 
  

  

  3 
  C)ne 
  belt 
  of 
  schist, 
  somewhat 
  more 
  complex 
  than 
  usual 
  by 
  

   reason 
  of 
  intrusions, 
  known 
  as 
  Manhattan 
  schist 
  on 
  the 
  New 
  York 
  

   side, 
  continues 
  into 
  Ridgefield, 
  Conn, 
  but 
  on 
  the 
  Connecticut 
  map 
  

   is 
  not 
  differentiated 
  from 
  the 
  " 
  Becket 
  " 
  gneiss. 
  

  

  In 
  the 
  Poughkeepsie 
  quadrangle 
  the 
  work 
  of 
  areal 
  survey 
  has 
  

   been 
  carried 
  on 
  by 
  Prof. 
  C. 
  E. 
  Gordon. 
  This 
  quadrangle 
  embraces 
  

   a 
  portion 
  of 
  the 
  Highlands 
  of 
  southeastern 
  New 
  York, 
  known 
  

   generally 
  as 
  the 
  Fishkill 
  mountains, 
  which 
  on 
  the 
  north 
  are 
  over- 
  

   lapped 
  by 
  and 
  faulted 
  with 
  the 
  lower 
  Paleozoics 
  which 
  extend 
  

   northward 
  in 
  the 
  Hudson 
  valley. 
  Frequently 
  the 
  Highland 
  mass 
  

   has 
  overridden 
  the 
  newer 
  strata 
  and 
  presents 
  today 
  many 
  anomalous 
  

   relationships 
  with 
  the 
  latter. 
  From 
  these 
  clearly 
  marked 
  and 
  

  

  