﻿FOURTH 
  REPORT 
  OF 
  THE 
  DIRECTOR 
  I907 
  1 
  3 
  

  

  Both 
  the 
  Potsdam 
  and 
  the 
  Theresa 
  formations 
  have 
  large 
  repre- 
  

   sentation 
  on 
  the 
  Alexandria 
  quadrangle, 
  but 
  the 
  chief 
  interest 
  

   attaches 
  to 
  the 
  Precambric 
  rocks. 
  The 
  main 
  rock 
  of 
  the 
  Thousand 
  

   Island 
  region 
  is 
  a 
  granite 
  gneiss, 
  a 
  bathylith 
  of 
  probable 
  Laurentian 
  

   age. 
  Near 
  its 
  edges 
  it 
  holds 
  abundant 
  inclusions 
  of 
  schists, 
  and 
  

   passes 
  by 
  increase 
  of 
  these 
  into 
  a 
  belt 
  of 
  schists 
  cut 
  by 
  granite, 
  

   these 
  dikes 
  diminishing 
  as 
  one 
  recedes 
  from 
  the 
  main 
  granite 
  mass. 
  

   There 
  is 
  much 
  in 
  these 
  schists 
  to 
  suggest 
  that 
  they 
  are 
  impure 
  lime- 
  

   stones 
  transformed 
  by 
  the 
  contact 
  action 
  of 
  the 
  granite 
  gneiss. 
  

   This 
  Alexandria 
  bathylith 
  seems 
  to 
  have 
  been 
  much 
  richer 
  in 
  miner- 
  

   alizing 
  agents 
  than 
  was 
  the 
  similar 
  Antwerp 
  bathylith 
  of 
  the 
  Theresa 
  

   quadrangle. 
  A 
  coarse 
  granite 
  is 
  also 
  present 
  which 
  seems 
  of 
  later 
  

   date. 
  

  

  Eastern 
  Adirondacks. 
  For 
  a 
  number 
  of 
  years, 
  Prof. 
  James 
  F. 
  

   Kemp, 
  who 
  has 
  excellently 
  served 
  the 
  State 
  work 
  in 
  geology, 
  has 
  

   continued 
  his 
  investigations 
  in 
  the 
  eastern 
  Adirondacks. 
  Under 
  the 
  

   auspices 
  of 
  the 
  United 
  States 
  Geological 
  Survey 
  Professor 
  Kemp 
  

   has 
  long 
  devoted 
  close 
  attention 
  to 
  the 
  intricate 
  problems 
  presented 
  

   by 
  the 
  crystalline 
  rock 
  region 
  of 
  the 
  Elizabeth 
  town, 
  Ausable, 
  Mt 
  

   Marcy 
  and 
  Lake 
  Placid 
  quadrangles. 
  By 
  an 
  arrangement 
  entered 
  

   into 
  with 
  Professor 
  Kemp, 
  the 
  Director 
  of 
  the 
  United 
  States 
  

   Geological 
  Survey 
  and 
  the 
  Director 
  of 
  the 
  New 
  York 
  State 
  Survey, 
  

   this 
  work 
  is 
  now 
  transferred 
  to 
  the 
  supervision 
  of 
  this 
  office 
  with 
  

   full 
  assent 
  to 
  the 
  eventual 
  publication 
  here 
  of 
  all 
  the 
  results 
  acquired 
  

   whenever 
  the 
  work 
  shall 
  have 
  been 
  completed. 
  Under 
  this 
  under- 
  

   standing,- 
  Professor 
  Kemp 
  has 
  reviewed 
  and 
  continued 
  his 
  work 
  

   on 
  these 
  quadrangles. 
  Some 
  problems 
  which 
  seemed 
  determined 
  in 
  

   the 
  past 
  have 
  been 
  of 
  necessity 
  reopened, 
  for 
  it 
  was 
  inevitable 
  that 
  

   there 
  should 
  be 
  some 
  gaps 
  in 
  the 
  record 
  and 
  some 
  former 
  deter- 
  

   minations 
  requiring 
  corroboration. 
  During 
  the 
  past 
  season 
  Pro- 
  

   fessor 
  Kemp's 
  work 
  has 
  been 
  concentrated 
  upon 
  the 
  Elizabethtown 
  

   quadrangle, 
  which 
  is 
  not 
  only 
  the 
  most 
  thickly 
  settled 
  of 
  the 
  four 
  

   mentioned 
  but 
  economically 
  the 
  most 
  important. 
  Since 
  the 
  earlier 
  

   neldwork 
  in 
  this 
  area 
  was 
  done, 
  in 
  1896-97, 
  we 
  have 
  come 
  to 
  

   recognize 
  the 
  great 
  syenitic 
  series 
  of 
  eruptive 
  rocks 
  which 
  was 
  im- 
  

   perfectly 
  noted 
  under 
  other 
  terms 
  in 
  earlier 
  reports 
  and 
  thus 
  made 
  

   to 
  accord 
  with 
  a 
  scheme 
  of 
  classification 
  at 
  that 
  time 
  apparently 
  

   satisfactory. 
  This 
  area, 
  moreover, 
  is 
  on 
  the 
  border 
  between 
  the 
  

   central 
  anorthosite 
  mass 
  and 
  the 
  outer 
  Grenville 
  sedimentary 
  and 
  

   other 
  gneisses. 
  There 
  are 
  puzzling 
  intermediate 
  types 
  and 
  on 
  the 
  

   whole 
  a 
  complicated 
  assemblage 
  of 
  rocks 
  whose 
  relations 
  await 
  

   determination. 
  In 
  the 
  10 
  years 
  past 
  there 
  has 
  also 
  been 
  extensive 
  

  

  