﻿494 
  NEW 
  YORK 
  STATE 
  MUSEUM 
  

  

  micaceous 
  and 
  hornblendic 
  schists 
  on 
  the 
  point 
  a 
  few 
  rods 
  east 
  

   of 
  Rocky 
  point. 
  The 
  normal 
  weathering 
  with 
  smooth 
  rounding 
  

   surfaces 
  with 
  the 
  formation 
  of 
  small 
  crevices 
  by 
  solution 
  is 
  well 
  

   shown 
  in 
  plate 
  10. 
  

  

  The 
  island 
  near 
  the 
  south 
  shore 
  of 
  Seventh 
  lake 
  is 
  made 
  up 
  of 
  

   rusty 
  and 
  well 
  banded 
  gneisses 
  with 
  some 
  highly 
  impure 
  quart- 
  

   zose 
  limestone. 
  In 
  the 
  rusty 
  gneiss 
  are 
  thin 
  beds 
  of 
  chondroditic 
  

   limestone. 
  This 
  is 
  a 
  rare 
  rock 
  in 
  the 
  western 
  Adirondacks, 
  hav- 
  

   ing 
  been 
  previously 
  found 
  so 
  far 
  as 
  the 
  writer 
  is 
  aware 
  only 
  in 
  

   the 
  town 
  of 
  Rossie, 
  St 
  Lawrence 
  co. 
  In 
  the 
  present 
  case 
  

   the 
  chondrodite 
  is 
  of 
  a 
  rich 
  reddish 
  brown 
  color, 
  and 
  is 
  very 
  

   abundant, 
  affording 
  a 
  rock 
  of 
  a 
  beauty 
  seldom 
  surpassed. 
  

  

  The 
  rusty 
  gneiss 
  also 
  contains 
  many 
  lenses 
  and 
  veins 
  of 
  coarse 
  

   calcite 
  rich 
  in 
  quartz, 
  mica, 
  pyroxene, 
  etc. 
  This 
  calcite 
  dissolves 
  

   with 
  a 
  very 
  smooth 
  surface,^ 
  quite 
  unlike 
  the 
  rasp-like 
  surface 
  

   commonly 
  shown 
  by 
  weathered 
  crystalline 
  limestone, 
  and 
  as 
  a 
  

   result 
  of 
  this 
  solution 
  the 
  gneiss 
  is 
  full 
  of 
  cavities 
  containing 
  the 
  

   loosened 
  silicates, 
  etc. 
  

  

  Layers 
  of 
  almost 
  pure, 
  gray 
  tremolite 
  are 
  shown 
  and 
  other 
  

   layers 
  are 
  highly 
  micaceous. 
  Graphite 
  is 
  abundant 
  through 
  the 
  

   rocks, 
  while 
  veins, 
  lenses 
  and 
  irregular 
  masses 
  of 
  quartz 
  and 
  

   pegmatite 
  are 
  present 
  in 
  great 
  quantity. 
  

  

  While 
  there 
  is 
  some 
  variation 
  in 
  strike 
  and 
  dip, 
  the 
  ordinary 
  

   northeast 
  strike 
  and 
  steep 
  northerly 
  dip 
  predominate. 
  Plate 
  11 
  

   shows 
  this 
  locality 
  as 
  seen 
  from 
  the 
  lake. 
  

  

  The 
  great 
  variety 
  of 
  rock 
  shown 
  here 
  illustrates 
  in 
  a 
  striking 
  

   manner 
  the 
  general 
  rule 
  that 
  the 
  gneisses 
  which 
  are 
  of 
  undoubted 
  

   sedimentary 
  origin 
  vary 
  widely 
  within 
  narrow 
  limits 
  and 
  retain 
  

   much 
  of 
  their 
  original 
  bedded 
  character. 
  But 
  even 
  here 
  there 
  is 
  

   not 
  lacking 
  an 
  element 
  of 
  uncertainty; 
  for 
  there 
  are 
  present 
  two 
  

   layers 
  or 
  lenses 
  of 
  fine, 
  pink 
  granitic 
  gneiss, 
  quite 
  unlike 
  the 
  

   other 
  gneisses 
  and 
  in 
  every 
  respect 
  resembling 
  an 
  igneous 
  rock. 
  

   That 
  it 
  is 
  such 
  is 
  extremely 
  probable 
  and 
  yet 
  the 
  structural 
  data 
  

   presented 
  are 
  not 
  sufficient 
  to 
  establish 
  the 
  fact. 
  

  

  Rusty 
  and 
  gray 
  banded 
  gneisses 
  also 
  appear 
  on 
  the 
  adjacent 
  

   south 
  shore 
  and 
  on 
  the 
  north 
  shore 
  near 
  the 
  outlet, 
  and, 
  though 
  

  

  