﻿l8 
  NEW 
  YORK 
  STATE 
  MUSEUM 
  

  

  The 
  slates 
  present 
  many 
  lithologic 
  variations 
  and 
  many 
  inter-, 
  

   esting- 
  stratigraphic 
  and 
  structural 
  relations 
  which 
  can 
  not 
  be 
  

   given 
  here. 
  

  

  Metamorphism. 
  In 
  this 
  report 
  the 
  general 
  fact 
  of 
  greater 
  

   metamorphism 
  of 
  the 
  Paleozoics 
  to 
  the 
  east 
  should 
  be 
  noted. 
  

   Reconnaissance 
  in 
  Dutchess 
  county 
  reveals 
  that 
  the 
  metamorphism 
  

   of 
  these 
  rocks 
  is 
  a 
  function 
  of 
  the 
  distance 
  of 
  these 
  strata 
  from 
  the 
  

   Hudson 
  river 
  in 
  the 
  northern 
  portion 
  of 
  the 
  county. 
  At 
  the 
  south 
  

   apparently 
  the 
  increment 
  by 
  which 
  metamorphism 
  approaches 
  a 
  

   given 
  degree 
  is 
  greater 
  per 
  unit 
  distance, 
  and 
  apparently 
  is 
  in 
  

   some 
  way 
  related 
  to 
  the 
  proximity 
  of 
  the 
  Highlands 
  mass. 
  

  

  The 
  map 
  and 
  complete 
  presentation 
  of 
  details 
  and 
  conclusions 
  

   are 
  reserved 
  for 
  a 
  later 
  and 
  fuller 
  report 
  on 
  the 
  geology 
  of 
  the 
  

   Poughkeepsie 
  quadrangle. 
  

  

  Surficial 
  geology 
  

  

  The 
  examination 
  of 
  the 
  glacial 
  and 
  postglacial 
  deposits 
  and 
  their 
  

   interpretation 
  in 
  terms 
  of 
  the 
  agents 
  performing 
  the 
  work 
  has 
  

   been 
  continued 
  during 
  the 
  past 
  season 
  by 
  Prof. 
  H. 
  L. 
  Fairchild 
  in 
  

   the 
  region 
  about 
  the 
  east 
  end 
  of 
  Lake 
  Ontario, 
  especially 
  in 
  the 
  

   area 
  covered 
  by 
  the 
  Grindstone, 
  Alexandria 
  Bay, 
  Cape 
  Vincent, 
  

   Clayton 
  and 
  Theresa 
  cjuadrangles. 
  The 
  glacial 
  and 
  glaciolacustrine 
  

   features 
  are 
  striking 
  and 
  peculiar; 
  over 
  all 
  the 
  area 
  the 
  deposits 
  

   were 
  laid 
  down 
  under 
  the 
  deep 
  waters 
  of 
  Lake 
  Iroquois 
  and 
  the 
  

   north 
  and 
  east 
  portions 
  of 
  the 
  area 
  were 
  also 
  covered 
  by 
  the 
  marine 
  

   waters 
  of 
  Gilbert 
  gulf. 
  In 
  the 
  lowering 
  of 
  these 
  waters 
  all 
  the 
  land 
  

   surfaces 
  were 
  wave 
  swept 
  and 
  in 
  consequence 
  the 
  drift 
  is 
  mostly 
  

   gathered 
  into 
  the 
  depressions. 
  The 
  two 
  striking 
  drift 
  features 
  are 
  

   the 
  extensive 
  clay 
  plains 
  which 
  occupy 
  the 
  valleys 
  and 
  the 
  lower 
  

   tracts 
  and 
  the 
  few 
  boulder 
  moraines. 
  The 
  drift 
  sheet 
  as 
  a 
  whole 
  

   is 
  scanty 
  and 
  many 
  extensive 
  tracts 
  are 
  essentially 
  bare 
  rock. 
  The 
  

   striking 
  physiographic 
  features 
  are 
  the 
  hummocks 
  or 
  rock 
  knobs 
  

   in 
  the 
  districts 
  of 
  crystalline 
  rocks, 
  the 
  broad 
  plains 
  produced 
  by 
  

   the 
  sedimentaries 
  and 
  the 
  clay 
  plains 
  of 
  the 
  lowlands 
  and 
  valleys- 
  

   Suggestions 
  are 
  found 
  of 
  a 
  Pre 
  Wisconsin 
  glaciation, 
  though 
  no 
  

   interglacial 
  or 
  warm 
  climate 
  deposits 
  are 
  yet 
  determined. 
  Over 
  

   large 
  tracts 
  of 
  the 
  limestone 
  the 
  surface 
  has 
  been 
  worn 
  into 
  broad 
  

   furrows 
  and 
  ridges, 
  a 
  huge 
  " 
  washboard 
  " 
  structure 
  which 
  has 
  lost 
  

   its 
  original 
  glacial 
  polish 
  and 
  striae. 
  A 
  later 
  ice 
  abrasion 
  has 
  cut 
  

   these 
  parallel 
  ridges 
  usually 
  at 
  a 
  considerable 
  angle. 
  The 
  old 
  

   planation 
  surfaces 
  have 
  lost 
  much 
  of 
  their 
  glacial 
  character. 
  In 
  

  

  