﻿GEOLOGY 
  OF 
  SARATOGA 
  SPRINGS 
  AND 
  VICINITY 
  99 
  

  

  The 
  fossils 
  which 
  are 
  most 
  frequently 
  met 
  with 
  in 
  the 
  shales 
  

   are 
  : 
  the 
  graptolites 
  Corynoides 
  gracilis, 
  D; 
  i 
  c 
  r 
  a 
  n 
  o 
  - 
  

   graptus 
  nicholsoni, 
  Diplograptus 
  amplexi- 
  

   caulis, 
  D. 
  amplexicaulis 
  var. 
  pertenuis, 
  Clima- 
  

   cograptus 
  spiniferus, 
  and 
  the 
  little 
  gastropod 
  A 
  r 
  c 
  h 
  i 
  - 
  

   nacella 
  orbiculata 
  and 
  little 
  lamellibranchs 
  of 
  the 
  genera 
  

   Clidophorus 
  and 
  Ctenodonta, 
  while 
  the 
  limestone 
  and 
  grit 
  bands 
  

   contain 
  the 
  brachiopods 
  Dalmanella 
  testudinaria, 
  

   Plectambonites 
  sericeus, 
  fragments 
  of 
  Rafinesquina 
  

   and 
  crinoid 
  joints. 
  Rarely 
  a 
  larger 
  fauna 
  of 
  mollusks 
  and 
  trilobites 
  

   occurs, 
  as 
  at 
  Snake 
  hill, 
  and 
  some 
  places 
  in 
  Albany 
  county. 
  Also 
  

   worms 
  similar 
  to 
  those 
  described 
  from 
  the 
  Canajoharie 
  shale 
  are 
  

   frequently 
  seen. 
  

  

  The 
  frequent 
  occurrence 
  of 
  Dicrano 
  graptus 
  nichol- 
  

   soni 
  typus 
  which 
  is 
  not 
  found 
  in 
  the 
  Normanskill 
  shale, 
  appears 
  

   to 
  us 
  especially 
  characteristic 
  of 
  this 
  formation, 
  especially 
  about 
  

   Saratoga 
  lake, 
  while 
  Lasiograptus 
  eucharis, 
  which 
  is 
  

   extremely 
  common 
  in 
  the 
  Canajoharie 
  shale, 
  is 
  here 
  less 
  frequently 
  

   met 
  with. 
  

  

  Correlation. 
  From 
  the 
  fauna 
  of 
  the 
  Snake 
  Hill 
  beds 
  it 
  can 
  be 
  

   inferred 
  that 
  the 
  formation 
  is 
  of 
  early 
  Trenton 
  age 
  and 
  roughly 
  

   corresponds 
  to 
  the 
  lower 
  and 
  perhaps 
  part 
  of 
  the 
  middle 
  Trenton. 
  

   It 
  probably 
  rests 
  upon 
  the 
  upper 
  division 
  of 
  the 
  Normanskill 
  shale 
  

   and 
  is 
  the 
  youngest 
  of 
  the 
  rock 
  formations 
  of 
  the 
  Levis 
  basin 
  that 
  

   by 
  overthrusting 
  and 
  intensive 
  folding 
  have 
  been 
  pushed 
  westward 
  

   into 
  contact 
  with 
  the 
  formations 
  of 
  the 
  Mohawk-Champlain 
  basin 
  

   (see 
  diagram, 
  page 
  140). 
  

  

  STRUCTURAL 
  GEOLOGY 
  OF 
  THE 
  SHALE 
  BELT 
  

  

  BY 
  R. 
  RUEDEMANN 
  

  

  The 
  principal 
  structural 
  feature 
  of 
  the 
  shale 
  belt 
  of 
  the 
  two 
  

   quadrangles 
  finds 
  its 
  expression 
  in 
  the 
  contrast 
  of 
  the 
  flat-lying 
  

   or 
  but 
  slightly 
  dipping 
  shales 
  of 
  the 
  western 
  trough 
  and 
  the 
  in- 
  

   tensely 
  folded 
  and 
  crumpled 
  condition 
  of 
  all 
  the 
  rocks 
  east 
  of 
  this 
  

   belt. 
  

  

  The 
  boundary 
  line 
  between 
  the 
  folded 
  and 
  flat 
  shale 
  areas 
  co- 
  

   incides 
  very 
  nearly 
  with 
  that 
  between 
  the 
  Canajoharie 
  and 
  Snake 
  

   Hill 
  shales, 
  not 
  only 
  on 
  the 
  two 
  quadrangles 
  here 
  described, 
  but 
  in 
  

   the 
  entire 
  inner 
  lowland 
  extending 
  from 
  the 
  Helderberg 
  cuesta 
  

   to 
  the 
  Adirondacks 
  and 
  then 
  into 
  the 
  Champlain 
  basin 
  and 
  presum- 
  

   ably 
  farther 
  north. 
  It 
  does 
  not 
  coincide 
  exactly 
  because 
  in 
  some 
  

  

  