﻿GEOLOGY 
  OF 
  SARATOGA 
  SPRINGS 
  AND 
  VICINITY 
  I35 
  

  

  every 
  allowance 
  for 
  that 
  it 
  still 
  seems 
  to 
  us 
  that 
  the 
  very 
  oldest 
  

   Tertiary 
  is 
  the 
  youngest 
  age 
  that 
  can 
  possibly 
  be 
  ascribed 
  to 
  the 
  

   rock, 
  all 
  the 
  conditions 
  considered. 
  Since 
  igneous 
  action 
  of 
  such 
  age, 
  

   or 
  of 
  any 
  Tertiary 
  age, 
  is 
  wholly 
  unknown 
  in 
  the 
  eastern 
  United 
  

   States, 
  a 
  reference 
  to 
  the 
  Newark 
  seems 
  to 
  us 
  more 
  reasonable. 
  

   Yet 
  we 
  candidly 
  admit 
  the 
  peculiarity 
  of 
  the 
  rock 
  and 
  its 
  isolated 
  

   occurrence, 
  and 
  have 
  no 
  quarrel 
  with 
  anyone 
  who 
  is 
  disposed 
  to 
  

   take 
  a 
  different 
  view. 
  There 
  is 
  one 
  character 
  of 
  the 
  lava 
  which 
  

   suggests 
  recency, 
  and 
  that 
  is 
  the 
  unaltered 
  and 
  undevitrified 
  char- 
  

   acter 
  of 
  the 
  glass. 
  

  

  To 
  sum 
  up, 
  the 
  only 
  definite 
  statement 
  that 
  can 
  be 
  made 
  concern- 
  

   ing 
  the 
  knob 
  is 
  that 
  it 
  consists 
  of 
  a 
  small 
  mass 
  of 
  lava 
  of 
  effusive 
  

   type. 
  If 
  it 
  is 
  in 
  place 
  it 
  seems 
  surely 
  a 
  volcanic 
  neck 
  or 
  throat; 
  

   if 
  not 
  in 
  place 
  it 
  may 
  be 
  a 
  fragment 
  of 
  a 
  surface 
  flow, 
  overthrust 
  

   from 
  some 
  locality 
  to 
  the 
  east. 
  If 
  in 
  place 
  it 
  is 
  younger 
  than 
  

   the 
  date 
  of 
  the 
  overthrusting 
  ; 
  if 
  not 
  in 
  place 
  it 
  is 
  older. 
  If 
  not 
  

   in 
  place 
  we 
  have 
  no 
  idea 
  whence 
  it 
  came, 
  nor 
  are 
  any 
  other 
  frag- 
  

   ments 
  known. 
  It 
  has 
  some 
  features 
  in 
  common 
  with 
  certain 
  New- 
  

   ark 
  trap 
  flows 
  and 
  is 
  like 
  some 
  of 
  them 
  in 
  composition, 
  though 
  

   the 
  composition 
  differs 
  from 
  that 
  of 
  the 
  average 
  Newark 
  trap. 
  

   Clear 
  structural 
  evidence 
  of 
  much 
  shearing 
  and 
  faulting 
  of 
  the 
  

   knob, 
  of 
  such 
  type 
  as 
  to 
  indicate 
  deformation 
  under 
  load, 
  leads 
  to 
  

   the 
  conviction 
  that 
  the 
  lava 
  can 
  not 
  be 
  an 
  especially 
  recent 
  one. 
  

  

  HISTORICAL 
  GEOLOGY 
  

  

  BY 
  H. 
  P. 
  CUSHING 
  AND 
  R. 
  RUEDEMANN 
  

  

  Precambric. 
  Our 
  direct 
  knowledge 
  of 
  the 
  events 
  of 
  Precambric 
  

   time 
  in 
  the 
  region 
  commences 
  with 
  the 
  deposition 
  of 
  the 
  Grenville 
  

   series. 
  These 
  rocks 
  are 
  very 
  widespread 
  and 
  very 
  thick, 
  with 
  

   great 
  amounts 
  of 
  shales 
  and 
  limestones 
  and 
  a 
  lesser 
  amount 
  of 
  

   sandstone. 
  They 
  must 
  have 
  been 
  deposited 
  on 
  some 
  floor 
  of 
  older 
  

   rocks 
  which 
  has 
  since 
  been 
  entirely 
  destroyed 
  by 
  igneous 
  action, 
  

   or 
  else 
  yet 
  remains 
  to 
  be 
  discovered. 
  Judging 
  by 
  their 
  extent 
  and 
  

   thickness 
  the 
  series 
  was 
  probably 
  deposited 
  under 
  marine 
  conditions 
  

   but, 
  lacking 
  fossils, 
  there 
  can 
  be 
  no 
  certainty 
  in 
  the 
  matter. 
  

  

  Following 
  the 
  deposit 
  of 
  the 
  Grenville 
  sediments 
  the 
  region 
  was 
  

   repeatedly 
  invaded 
  from 
  beneath 
  by 
  great 
  masses 
  of 
  igneous 
  rock. 
  

   The 
  earliest 
  and 
  most 
  widespread 
  of 
  these 
  invasions 
  was 
  that 
  of 
  the 
  

   Laurentian 
  granite. 
  Subsequently 
  came 
  invasions 
  of 
  anorthosite, 
  

   syenite, 
  granite 
  and 
  gabbro. 
  These 
  broke 
  up 
  the 
  Grenville 
  rocks 
  

   into 
  groups 
  of 
  fragments, 
  apparently 
  ate 
  away 
  and 
  digested 
  much 
  

  

  