﻿GEOLOGY 
  OF 
  THOUSAND 
  ISLANDS 
  REGION 
  QI 
  

  

  on 
  the 
  stoss-seite 
  of 
  the 
  hills. 
  But 
  since 
  the 
  thin 
  limestone 
  slabs 
  

   over 
  the 
  Trenton 
  belt 
  have 
  been 
  incorporated 
  in 
  great 
  quantities 
  

   into 
  the 
  drift, 
  whence 
  they 
  have 
  found 
  their 
  way 
  into 
  the 
  stone 
  

   fences, 
  these 
  stone 
  fences 
  composed 
  of 
  thin 
  Trenton 
  slabs 
  are 
  al- 
  

   most 
  the 
  most 
  characteristic 
  feature 
  of 
  the 
  Trenton 
  formation 
  in 
  

   the 
  district 
  and 
  they 
  are 
  remarkably 
  closely 
  bound 
  to 
  the 
  present 
  

   distribution 
  of 
  the 
  Trenton. 
  

  

  The 
  contact 
  between 
  the 
  Black 
  River 
  and 
  Trenton 
  groups 
  is 
  but 
  

   rarely 
  seen, 
  but 
  where 
  found, 
  it 
  indicates 
  an 
  unconformity, 
  either 
  

   by 
  the 
  irregularity 
  of 
  the 
  contact 
  line, 
  as 
  at 
  the 
  Klock 
  quarry 
  at 
  

   Watertown, 
  or 
  by 
  the 
  presence 
  of 
  a 
  basal 
  conglomerate 
  bed 
  in 
  the 
  

   Trenton 
  as 
  at 
  Threemile 
  Bay. 
  

  

  The 
  best 
  continuous 
  exposure, 
  or 
  in 
  fact 
  the 
  only 
  good 
  one 
  within 
  

   the 
  boundaries 
  of 
  the 
  mapped 
  area, 
  is 
  that 
  found 
  along 
  a 
  brook 
  at 
  

   the 
  western 
  outskirts 
  of 
  the 
  village 
  of 
  Threemile 
  Bay 
  [pi. 
  24, 
  25]. 
  

   This 
  section 
  is 
  given 
  below. 
  Another 
  fairly 
  complete 
  section 
  can 
  

   be 
  obtained 
  from 
  Klock's 
  quarry 
  to 
  the 
  top 
  of 
  Pinnacle 
  hill 
  at 
  

   Watertown 
  and 
  a 
  third, 
  which 
  however 
  lacks 
  the 
  base, 
  at 
  the 
  west 
  

   end 
  of 
  Carleton 
  island 
  in 
  the 
  St 
  Lawrence 
  river. 
  

  

  Section 
  of 
  lower 
  Trenton 
  limestone 
  at 
  Threemile 
  Bay 
  

  

  (generalized) 
  

   i6'-i7' 
  Fine 
  grained 
  thin 
  bedded 
  limestone 
  with 
  shaly 
  intercalations 
  

   3' 
  Thin 
  bedded 
  limestone 
  layers 
  with 
  shaly 
  intercalations, 
  rich 
  in 
  

  

  lamellibranchs, 
  gastropods 
  and 
  cephalopods 
  

   10' 
  Fine 
  grained 
  black 
  limestone 
  with 
  shaly 
  partings, 
  in 
  part 
  barren, 
  

   in 
  part 
  full 
  of 
  fossils 
  on 
  shaly 
  partitions, 
  mostly 
  large 
  conical 
  

   or 
  hemispheric 
  bryozoans 
  (Prasopora 
  simulatrix) 
  in 
  

   horizon 
  about 
  2 
  feet 
  from 
  base 
  

   3' 
  6" 
  Black, 
  fine 
  grained 
  limestone 
  full 
  of 
  worm 
  tubes, 
  no 
  other 
  fossils 
  

   5' 
  6" 
  Gray, 
  crystalline, 
  thin 
  bedded 
  limestone 
  with 
  many 
  crinoid 
  joints 
  

   on 
  top 
  (2 
  feet) 
  and 
  fine 
  grained 
  dark 
  thin 
  bedded 
  limestone 
  

   below, 
  with 
  shaly 
  intercalations. 
  The 
  limestone 
  beds 
  full 
  of 
  

   brachiopods 
  (Dalmanella, 
  Rafinesquina) 
  and 
  bryozoans 
  

   6' 
  Dark 
  gray 
  to 
  black 
  compact 
  limestone, 
  in 
  strata 
  i 
  foot 
  thick 
  with 
  

   thin 
  shaly 
  partings. 
  Very 
  fossiliferous. 
  Dalmanella 
  

   testudinaria, 
  Plectambonites 
  sericeus, 
  

   Calymmene, 
  bryozoans 
  (Pachydictya 
  acuta) 
  and 
  

   crinoid 
  joints 
  

   5" 
  Conglomerc^te 
  bed 
  with 
  crystalline 
  matrix 
  and 
  crinoid 
  joints 
  

   Base 
  of 
  Trenton 
  

   Black 
  River 
  beds 
  

  

  It 
  follows 
  from 
  this 
  and 
  the 
  other 
  sections 
  that 
  the 
  Trenton 
  

   begins 
  with 
  a 
  thin 
  conglomeratic 
  bed, 
  on 
  which 
  rest 
  about 
  6 
  feet 
  

   of 
  dark 
  gray 
  to 
  black 
  compact 
  limestone, 
  in 
  beds 
  about 
  i 
  foot 
  

   thick, 
  with 
  thin 
  shaly 
  partings. 
  The 
  latter 
  are 
  very 
  fossiliferous, 
  

   containing 
  most 
  profusely 
  Dalmanella 
  testudinaria, 
  

   Plectambonites 
  sericeus, 
  Pachydictya 
  acuta 
  

   and 
  crinoid 
  joints. 
  

  

  