﻿22 
  NEW 
  YORK 
  STATE 
  MUSEUM 
  

  

  in 
  the 
  St 
  Lawrence 
  and 
  Champlain 
  valleys, 
  other 
  formations 
  

   come 
  in 
  whose 
  exact 
  relationships 
  have 
  not 
  yet 
  been 
  made 
  out. 
  

   According 
  to 
  Ulrich 
  the 
  Pamelia 
  is 
  to 
  be 
  correlated 
  with 
  a 
  part 
  

   of 
  the 
  Chazy 
  of 
  the 
  Champlain 
  valley. 
  P'or 
  a 
  long 
  time 
  the 
  

   Pamelia 
  had 
  been 
  described 
  and 
  mapped 
  as 
  Beekmantown 
  lime- 
  

   stone, 
  but 
  it 
  now 
  seems 
  to 
  be 
  pretty 
  well 
  established 
  that 
  the 
  

   true 
  Beekmantow^n 
  is 
  not 
  present 
  along 
  the 
  northwestern 
  Ad- 
  

   irondacks. 
  

  

  The 
  Pamelia 
  formation 
  (Lower 
  Siluric) 
  is 
  the 
  oldest 
  sedi- 
  

   mentary 
  mass 
  exposed 
  within 
  the 
  limits 
  of 
  the 
  quadrangle. 
  Its 
  

   outcropping 
  edge, 
  which 
  extends 
  from 
  north 
  to 
  south 
  across 
  the 
  

   district, 
  everywhere 
  rests 
  directly 
  upon 
  the 
  Precambric 
  rocks. 
  

   Since 
  it 
  outcrops 
  at 
  the 
  base 
  of 
  the 
  steep 
  slope 
  facing 
  Black 
  

   river 
  its 
  surface 
  exposure 
  is 
  small. 
  The 
  actual 
  contact 
  with 
  the 
  

   Precambric 
  may 
  be 
  seen 
  in 
  at 
  least 
  three 
  places 
  as 
  follows: 
  

   Where 
  the 
  railroad 
  crosses 
  Roaring 
  brook 
  near 
  Martinsburg 
  

   station; 
  along 
  the 
  creek 
  i^ 
  miles 
  northwest- 
  north 
  of 
  Lyons 
  

   Falls 
  ; 
  and 
  along 
  the 
  railroad 
  ^ 
  of 
  a 
  mile 
  north 
  of 
  Port 
  Leyden. 
  

   At 
  a 
  number 
  of 
  other 
  places 
  the 
  contact 
  is 
  almost 
  visible. 
  The 
  

   bed 
  in 
  actual 
  contact 
  with 
  the 
  Precambric 
  is 
  always 
  a 
  sandy 
  

   conglomerate 
  above 
  which 
  occur 
  several 
  feet 
  of 
  calcareous 
  sand- 
  

   stones, 
  then 
  a 
  few 
  feet 
  of 
  bluish 
  black, 
  fossiliferous 
  limestone, 
  

   and 
  finally 
  thin 
  to 
  thick 
  bedded, 
  whitish 
  gray 
  to 
  bluish 
  gray, 
  

   rather 
  impure 
  limestones 
  which 
  latter 
  make 
  up 
  more 
  than 
  half 
  

   the 
  section. 
  Many 
  of 
  the 
  upper, 
  gray 
  beds 
  are 
  really 
  magnesian 
  

   limestones 
  which 
  may 
  be 
  burned 
  for 
  waterlime 
  as 
  has 
  been 
  done 
  

   at 
  Lowville. 
  The 
  conglomerate 
  and 
  sandstone 
  at 
  the 
  base 
  of 
  

   the 
  Pamelia 
  represent 
  the 
  materials 
  derived 
  from 
  the 
  Precam- 
  

   bric 
  land 
  surface 
  as 
  the 
  sea 
  encroached 
  upon 
  it. 
  According 
  to 
  

   the 
  observations 
  of 
  Professor 
  Gushing 
  on 
  the 
  Theresa 
  quadrangle 
  

   (northward), 
  w^hich 
  are 
  corroborated 
  by 
  the 
  writer 
  on 
  the 
  Port 
  

   Leyden 
  quadrangle, 
  the 
  basal 
  conglomerate 
  and 
  sandstone 
  rep- 
  

   resents 
  a 
  shifting 
  upward 
  horizon, 
  due 
  to 
  overlap, 
  as 
  the 
  sea 
  

   encroached 
  upon 
  the 
  land 
  from 
  west 
  to 
  east. 
  These 
  basal 
  beds 
  

   are 
  more 
  than 
  likely 
  to 
  be 
  correlated 
  with 
  the 
  Rideau 
  sandstone 
  

   as 
  described 
  by 
  Ami 
  in 
  Ontario, 
  Canada. 
  

  

  Following 
  is 
  a 
  detailed 
  section 
  made 
  by 
  Professor 
  Cushing 
  

   along 
  Roaring 
  brook 
  (near 
  Martinsburg 
  station) 
  and 
  kindly 
  fur- 
  

   nished 
  to 
  the 
  writer 
  : 
  

  

  4 
  inches 
  of 
  blue 
  gray 
  calcareous 
  shale 
  above 
  and 
  9 
  inches 
  of 
  j-eet 
  Inches 
  

   same 
  beneath 
  with 
  a 
  4-inch 
  layer 
  of 
  mottled 
  blue 
  limestone 
  

   like 
  that 
  beneath 
  i 
  5 
  

  

  