﻿GEOLOGY 
  OF 
  SARATOGA 
  SPRINGS 
  AND 
  VICINITY 
  I33 
  

  

  we 
  can 
  not 
  relieve 
  ourselves 
  of 
  the 
  suspicion 
  that 
  it 
  may, 
  after 
  all, 
  

   be 
  an 
  overthrust 
  mass, 
  a 
  fragment 
  of 
  a 
  surface 
  flow 
  which 
  came 
  

   up 
  through 
  and 
  was 
  poured 
  out 
  upon 
  a 
  surface 
  of 
  limestone, 
  thus 
  

   acquiring 
  its 
  inclusions, 
  and 
  later 
  on 
  thrust 
  westward 
  coming 
  to 
  

   rest 
  with 
  rocks 
  with 
  which 
  it 
  had 
  originally 
  little 
  to 
  do. 
  

  

  The 
  inclusions. 
  The 
  difficulty 
  of 
  accounting 
  for 
  the 
  limestone 
  

   inclusions 
  in 
  the 
  lava 
  has 
  already 
  been 
  mentioned. 
  The 
  inclusions 
  

   are 
  many, 
  and 
  all 
  of 
  one 
  kind 
  of 
  rock, 
  which 
  seems 
  perhaps 
  re- 
  

   ferable 
  to 
  the 
  Bald 
  Mountain 
  limestone, 
  but 
  certainly 
  to 
  no 
  other 
  

   of 
  the 
  rock 
  formations 
  of 
  the 
  region. 
  The 
  knob 
  lies 
  in 
  the 
  midst 
  

   of 
  overthrust 
  shales. 
  Just 
  what 
  their 
  thickness 
  is 
  at 
  the 
  spot 
  we 
  

   have 
  no 
  means 
  of 
  knowing; 
  but 
  it 
  is 
  quite 
  likely 
  considerable, 
  since 
  

   they 
  extend 
  5 
  miles 
  farther 
  west 
  before 
  thinning 
  out 
  to 
  disappear- 
  

   ance. 
  In 
  considering 
  the 
  manner 
  of 
  overthrusting 
  in 
  such 
  weak 
  

   shales 
  it 
  seems 
  reasonable, 
  if 
  not 
  obligatory, 
  to 
  suppose 
  that 
  the 
  

   thrust 
  was 
  carried 
  by 
  some 
  strong, 
  competent 
  stratum, 
  on 
  top 
  of 
  

   which 
  the 
  shales 
  were 
  carried 
  westward. 
  The 
  Bald 
  Mountain 
  

   limestone 
  is 
  the 
  first 
  formation 
  of 
  the 
  sort 
  beneath 
  the 
  Normans- 
  

   kill 
  shale, 
  in 
  the 
  eastern 
  basin 
  section, 
  and 
  it 
  is 
  therefore 
  not 
  un- 
  

   reasonable 
  to 
  suppose 
  that 
  it 
  is 
  present 
  underneath 
  the 
  shales 
  at 
  

   Stark's 
  knob. 
  If 
  so 
  it 
  probably 
  rests 
  on 
  the 
  western 
  basin 
  rocks, 
  

   most 
  likely 
  on 
  Canajoharie 
  shale. 
  That 
  the 
  structure 
  as 
  a 
  whole 
  

   is 
  not 
  so 
  simple 
  as 
  this, 
  that 
  the 
  shales 
  are 
  jumbled 
  indiscrim- 
  

   inately 
  together 
  to 
  a 
  certain 
  extent, 
  is 
  shown 
  by 
  the 
  presence 
  of 
  

   Schaghticoke 
  (Dictyonema) 
  shale 
  in 
  the 
  midst 
  of 
  the 
  Normans- 
  

   kill 
  near 
  the 
  knob. 
  Were 
  fossils 
  more 
  abundant, 
  many 
  such 
  mix- 
  

   tures 
  might 
  be 
  found. 
  This 
  suggests 
  that 
  a 
  confused 
  mixture 
  

   of 
  shales 
  may 
  have 
  moved 
  west 
  even 
  beyond 
  the 
  competent 
  stratum 
  

   which 
  carried 
  them, 
  falling 
  and 
  being 
  pushed 
  in 
  front 
  of 
  the 
  main 
  

   mass. 
  The 
  Bald 
  Mountain 
  limestone 
  therefore 
  may, 
  or 
  may 
  not, 
  

   be 
  present 
  below 
  ground 
  at 
  the 
  knob. 
  If 
  it 
  is 
  present 
  it 
  lies 
  nearer 
  

   the 
  surface 
  than 
  any 
  other 
  limestone, 
  with 
  shales 
  both 
  above 
  and 
  

   below 
  ; 
  and 
  it 
  is 
  likely 
  also 
  to 
  be 
  in 
  somewhat 
  shattered 
  condition, 
  

   so 
  that 
  it 
  would 
  readily 
  furnish 
  inclusions 
  to 
  an 
  igneous 
  rock 
  ris- 
  

   ing 
  through 
  it. 
  The 
  limestone 
  inclusions 
  can 
  therefore 
  be 
  plausibly 
  

   accounted 
  for 
  on 
  the 
  theory 
  that 
  the 
  lava 
  is 
  in 
  place. 
  The 
  lack 
  of 
  

   inclusions 
  of 
  shale 
  is 
  not 
  thus 
  explained; 
  but 
  the 
  carbon 
  content 
  

   of 
  the 
  lava 
  may 
  have 
  come 
  from 
  the 
  shale, 
  and 
  its 
  failure 
  to 
  fur- 
  

   nish 
  inclusions 
  may 
  be 
  due 
  to 
  the 
  physical 
  nature 
  of 
  the 
  rock. 
  

  

  So 
  far 
  as 
  the 
  inclusions 
  are 
  concerned, 
  therefore, 
  they 
  do 
  

   not 
  aid 
  in 
  the 
  decision 
  as 
  to 
  whether 
  the 
  lava 
  is 
  in 
  place 
  or 
  is 
  not. 
  

  

  