﻿610 
  Forty-seventh 
  Report 
  on 
  the 
  State 
  Museum. 
  

  

  posed 
  gneiss, 
  ferruginous 
  and 
  chloritic 
  material, 
  small 
  lenticular 
  

   masses 
  of 
  clay 
  and 
  chloritic 
  matter, 
  breccia 
  containing 
  Potsdam 
  

   sandstone 
  fragments, 
  crystalline 
  limestone, 
  quartzite, 
  etc., 
  

   and 
  Calciferous 
  sandrock. 
  The 
  interval 
  from 
  gneiss 
  to 
  Cal- 
  

   ciferous 
  "represents 
  the 
  Huronian, 
  Primordial 
  and 
  Potsdam." 
  

   " 
  These 
  formations 
  represented 
  elsewhere 
  by 
  many 
  thousand 
  feet 
  

   of 
  sediments 
  are 
  here 
  represented 
  by 
  from 
  a 
  few 
  inches 
  to 
  several 
  

   feet 
  of 
  breccia 
  and 
  loose 
  chloritic 
  and 
  ferruginous 
  material." 
  It 
  

   is 
  stated 
  that 
  part 
  of 
  the 
  ferruginous 
  and 
  chloritic 
  material 
  " 
  is 
  

   derived 
  from 
  the 
  decomposition 
  of 
  the 
  gneiss 
  with 
  some 
  slight 
  

   sedimentation." 
  

  

  At 
  the 
  time 
  of 
  my 
  examination 
  the 
  materials 
  immediately 
  below 
  

   the 
  breccia 
  were 
  so 
  deeply 
  weathered 
  that 
  I 
  could 
  form 
  no 
  

   definite 
  opinion 
  as 
  to 
  their 
  relations. 
  They 
  did 
  not, 
  however, 
  

   appear 
  to 
  be 
  the 
  products 
  of 
  sedimentation. 
  They 
  seem 
  to 
  merge 
  

   into 
  the 
  deeply 
  weathered 
  crystallines 
  below, 
  of 
  which 
  the 
  

   structure 
  is 
  still 
  evident. 
  The 
  breccia 
  is 
  sharply 
  separated 
  at 
  its 
  

   base, 
  as 
  I 
  believe 
  plate 
  8 
  clearly 
  shows. 
  Its 
  matrix 
  is 
  Calciferous 
  

   sandrock 
  and 
  it 
  merges 
  into 
  the 
  overlying 
  members, 
  the 
  f 
  ragmental 
  

   constituents 
  guadually 
  decreasing 
  in 
  number 
  and 
  size. 
  These 
  

   f 
  ragmental 
  materials 
  consist, 
  so 
  far 
  as 
  I 
  could 
  find, 
  solely 
  of 
  

   Calciferous 
  sandrock, 
  in 
  part 
  similar 
  to 
  the 
  matrix 
  and 
  in 
  part 
  

   of 
  a 
  somewhat 
  darker 
  variety 
  which 
  is 
  often 
  observed 
  near 
  the 
  

   base 
  of 
  the 
  formation 
  in 
  the 
  region 
  northward. 
  The 
  fragments 
  

   are 
  angular 
  or 
  subangular 
  and 
  in 
  a 
  few 
  cases 
  rounded. 
  They 
  vary 
  

   in 
  size 
  up 
  to 
  about 
  four 
  inches. 
  

  

  A.t 
  Little 
  Falls 
  the 
  Calciferous 
  sand 
  rock 
  is 
  seen 
  to 
  lie 
  directly 
  on 
  

   the 
  crystalline 
  rocks.* 
  There 
  are 
  many 
  exposures,! 
  and 
  in 
  all 
  cases 
  

   that 
  I 
  observed 
  the 
  lower 
  members 
  were 
  typically 
  Calciferous 
  

  

  * 
  Walcott, 
  Correlation 
  papers, 
  Cambrian, 
  U. 
  S. 
  Geol. 
  Survey, 
  Bull 
  No. 
  81, 
  p. 
  347. 
  

  

  t 
  Note 
  — 
  This 
  statement 
  of 
  many 
  exposures 
  of 
  the 
  Calciferous 
  sand 
  rock 
  tying 
  directly 
  upon 
  

   the 
  crystalline 
  rocks 
  is 
  an 
  interesting 
  one, 
  since, 
  in 
  the 
  two 
  or 
  three 
  pre- 
  viously 
  known 
  exposures 
  

   along 
  the 
  ttohawk 
  valley, 
  the 
  Calciferous 
  has 
  been 
  shown 
  to 
  be 
  separated 
  from 
  the 
  crystalline 
  

   rocks 
  by 
  an 
  intervening 
  deposit 
  At 
  Little 
  Fails, 
  on 
  the 
  south 
  side 
  of 
  the 
  river, 
  there 
  was 
  

   formerly 
  a 
  good 
  exposure, 
  but 
  which 
  in 
  recent 
  years 
  has 
  been 
  covered. 
  This 
  exposure, 
  how- 
  

   ever, 
  showed 
  the 
  base 
  of 
  the 
  Calciferous 
  res-ting 
  upon 
  a 
  ferrugineous 
  deposit 
  of 
  clay 
  and 
  sand, 
  

   having 
  a 
  thickness 
  of 
  about 
  eighteen 
  inches, 
  which 
  iutervened 
  between 
  the 
  Calciferous 
  and 
  the 
  

   crystalline 
  rocks. 
  Many 
  years 
  since 
  there 
  wis 
  a 
  locality 
  upon 
  the 
  north 
  side 
  of 
  the 
  Mohawk 
  at 
  

   ths 
  " 
  Noses" 
  where 
  the 
  succession 
  of 
  the 
  Calciferous 
  and 
  crystalline 
  rocks 
  was 
  exposed, 
  but 
  at 
  

   this 
  locaUty 
  therd 
  was 
  a 
  considerable 
  amount 
  of 
  material 
  intervening 
  between 
  the 
  two 
  which 
  

   could 
  not 
  be 
  identified 
  with 
  either 
  of 
  the 
  formations. 
  The 
  exposure 
  upon 
  the 
  south 
  side 
  of 
  the 
  

   tfohawk 
  has 
  already 
  been 
  referred 
  to, 
  and 
  the 
  section 
  in 
  the 
  report 
  of 
  the 
  State 
  geologist 
  for 
  

   the 
  year 
  1885 
  shows 
  the 
  order 
  of 
  succession 
  at 
  that 
  place.— 
  H. 
  

  

  