﻿FOURTH 
  REPORT 
  OF 
  THE 
  DIRECTOR 
  xCp7 
  II 
  

  

  Northern 
  New 
  York. 
  Since 
  my 
  last 
  report 
  the 
  Long 
  Lake 
  

   map 
  and 
  accompanying 
  report 
  by 
  Prof. 
  H. 
  P. 
  Cushing 
  have 
  been 
  

   issued. 
  

  

  Professor 
  Cushing's 
  work 
  in 
  the 
  past 
  season 
  has 
  continued 
  upon 
  

   the 
  Theresa 
  and 
  Alexandria 
  quadrangles 
  which 
  also 
  involve 
  prob- 
  

   lems 
  pertaining 
  to 
  both 
  the 
  crystalline 
  and 
  the 
  sedimentary 
  rocks. 
  

   The 
  mapping 
  of 
  the 
  former 
  was 
  completed 
  last 
  season. 
  In 
  the 
  

   work 
  on 
  the 
  Paleozoic 
  sediments 
  which 
  required 
  the 
  aid 
  of 
  a 
  paleon- 
  

   tologist, 
  Dr 
  Ruedemann 
  assisted 
  with 
  the 
  cooperation 
  by 
  invitation 
  

   of 
  Mr 
  E. 
  O. 
  Ulrich 
  of 
  the 
  United 
  States 
  Geological 
  Survey. 
  Mr 
  

   Ulrich's 
  intimate 
  acquaintance 
  with 
  rocks 
  of 
  similar 
  age 
  in 
  other 
  

   parts 
  of 
  the 
  country 
  rendered 
  his 
  collaboration 
  of 
  much 
  value. 
  

  

  During 
  the 
  previous 
  season 
  the 
  Potsdam 
  sandstone 
  had 
  been 
  

   studied 
  and 
  was 
  found 
  everywhere 
  to 
  grade 
  upward 
  into 
  a 
  dolo- 
  

   mite 
  formation 
  quite 
  like 
  the 
  rocks 
  which 
  elsewhere 
  immediately 
  

   overlie 
  the 
  Potsdam 
  around 
  the 
  Adirondacks 
  and 
  which 
  have 
  been 
  

   regarded 
  and 
  mapped 
  as 
  passage 
  beds 
  into 
  the 
  Beekmantown 
  for- 
  

   mation 
  above. 
  It 
  was 
  naturally 
  expected 
  that 
  the 
  Beekmantown 
  

   formation 
  would 
  be 
  present 
  here, 
  to 
  be 
  followed 
  in 
  proper 
  succession 
  

   by 
  the 
  Lowville, 
  Black 
  River 
  and 
  Trenton 
  limestones. 
  In 
  working 
  

   downward 
  from 
  the 
  Trenton 
  as 
  the 
  summit 
  rock 
  of 
  the 
  quadrangle, 
  

   the 
  Black 
  River 
  limestone 
  appeared 
  with 
  a 
  thickness 
  of 
  some 
  20 
  

   feet 
  and 
  with 
  a 
  sharp 
  lithologic 
  boundary 
  separating 
  it 
  from 
  the 
  

   Lowville 
  beneath. 
  

  

  The 
  upper 
  part 
  of 
  the 
  Lowville 
  proves 
  to 
  be 
  abundantly 
  fossil- 
  

   iferous, 
  but 
  when 
  followed 
  downward 
  these 
  fossiliferous 
  limestones 
  

   are 
  succeeded 
  by 
  others 
  which 
  carry 
  an 
  abundant 
  ostracode 
  fauna 
  

   but 
  with 
  little 
  else. 
  These 
  two 
  limestones 
  have 
  a 
  combined 
  thick- 
  

   ness 
  of 
  some 
  75 
  feet. 
  Just 
  beneath 
  them 
  follows 
  a 
  considerable 
  

   thickness 
  of 
  whitish, 
  very 
  impure 
  limestones, 
  sometimes 
  shaly, 
  

   alternating 
  with 
  occasional 
  beds 
  of 
  pure 
  limestone 
  and 
  of 
  dolomitic 
  

   limestone 
  with 
  again 
  an 
  ostracode 
  fauna. 
  This 
  mass 
  has 
  a 
  thickness 
  

   of 
  about 
  80 
  feet 
  and 
  beneath 
  it 
  lies 
  a 
  10 
  foot 
  mass 
  of 
  pure 
  blackish 
  

   limestone 
  with 
  many 
  fossils, 
  mainly 
  gastropods 
  but 
  with 
  some 
  

   cephalopods 
  and 
  trilobites. 
  There 
  is 
  some 
  mixture 
  of 
  Lowville 
  

   forms 
  in 
  this 
  fauna 
  but 
  in 
  the 
  main 
  it 
  consists 
  of 
  forms 
  which 
  

   do 
  not 
  pass 
  up 
  into 
  that 
  formation. 
  The 
  fauna 
  appears 
  to 
  be 
  one 
  not 
  

   before 
  noted 
  in 
  New 
  York, 
  and 
  according 
  to 
  Mr 
  Ulrich 
  seems 
  com- 
  

   parable 
  with 
  the 
  fauna 
  of 
  the 
  upper 
  Stones 
  River 
  formation 
  of 
  other 
  

   regions. 
  Its 
  close 
  association 
  with 
  the 
  Lowville, 
  both 
  stratigraphi- 
  

   cally 
  and 
  paleontologically, 
  seems 
  to 
  preclude 
  its 
  reference 
  to 
  the 
  

   Beekmantown 
  formation 
  and 
  its 
  fauna 
  is 
  wholly 
  different. 
  The 
  

  

  