﻿530 
  NEW 
  YORK 
  STATE 
  MUSEUM 
  

  

  The 
  two 
  valleys 
  just 
  referred 
  to 
  are 
  separated 
  by 
  a 
  high 
  ridge 
  

   of 
  gneiss, 
  known 
  as 
  Putnam 
  mountain, 
  which, 
  like 
  its 
  associates, 
  

   is 
  steep 
  to 
  the 
  west 
  and 
  of 
  more 
  gradual 
  slope 
  to 
  the 
  east. 
  On 
  the 
  

   east 
  again 
  and 
  lying 
  between 
  the 
  southern 
  prolongation 
  of 
  South 
  

   bay 
  and 
  of 
  Wood 
  creek 
  is 
  Pinnacle 
  mountain, 
  the 
  extension 
  of 
  

   the 
  ridge 
  of 
  crystallines 
  just 
  described 
  in 
  Whitehall. 
  It 
  also 
  

   has 
  a 
  steep 
  westerly 
  front 
  and 
  a 
  gradually 
  sloping 
  easterly 
  one. 
  

   A 
  deep 
  valley, 
  however, 
  on 
  its 
  eastern 
  side 
  divides 
  it 
  into 
  two 
  

   ridges. 
  In 
  the 
  valley 
  is 
  Pinnacle 
  pond 
  — 
  a 
  small 
  one, 
  that 
  does 
  

   not 
  appear 
  on 
  the 
  current 
  editions 
  of 
  the 
  Fort 
  Ann 
  sheet 
  of 
  the 
  

   U. 
  S. 
  geological 
  survey. 
  This 
  may 
  be 
  a 
  valley 
  due 
  in 
  part 
  to 
  the 
  

   erosion 
  of 
  crystalline 
  limestone. 
  

  

  The 
  southeastern 
  corner 
  of 
  Fort 
  Ann 
  consists 
  of 
  paleozoic 
  

   strata 
  in 
  minor 
  hillocks, 
  which 
  give 
  a 
  very 
  picturesque 
  and 
  diver- 
  

   sified 
  topography. 
  

  

  Our 
  field 
  work 
  in 
  1897 
  did 
  not 
  cover 
  all 
  of 
  Fort 
  Ann, 
  but 
  was 
  

   limited 
  to 
  the 
  ridge 
  between 
  Wood 
  creek 
  and 
  the 
  South 
  bay 
  

   extension, 
  and 
  to 
  the 
  northwest 
  corner 
  along 
  Lake 
  George.® 
  

  

  Series 
  1. 
  The 
  gneisses 
  cover 
  much 
  the 
  larger 
  portion 
  of 
  Fort 
  

   Ann, 
  and 
  exhibit 
  the 
  same 
  types 
  which 
  have 
  been 
  met 
  in 
  the 
  

   townships 
  to 
  the 
  north. 
  The 
  paleozoics 
  encroach 
  on 
  them 
  on 
  the 
  

   southeast 
  and 
  in 
  the 
  valley 
  which 
  sets 
  up 
  from 
  Fort 
  Ann 
  toward 
  

   South 
  bay. 
  On 
  the 
  shores 
  of 
  South 
  bay, 
  within 
  the 
  limits 
  of 
  

   Fort 
  Ann, 
  the 
  gneiss 
  is 
  a 
  richly 
  quartzose, 
  garnetiferous 
  variety 
  

   (the 
  South 
  Bay 
  type), 
  like 
  the 
  one 
  described 
  under 
  Whitehall 
  

   from 
  neighboring 
  parts 
  of 
  the 
  ridge. 
  It 
  consists 
  of 
  lenses 
  of 
  

   quartz 
  up 
  to 
  an 
  inch 
  (25 
  mm) 
  or 
  more 
  in 
  length 
  and 
  -J 
  inch 
  

   (3-4 
  mm) 
  in 
  thickness. 
  Garnets 
  to 
  one 
  quarter 
  inch 
  (6-8 
  mm) 
  are 
  

   distributed 
  through 
  the 
  mass. 
  Feldspathic 
  matter 
  is 
  a 
  subordi- 
  

   nate 
  component. 
  The 
  outcrop 
  of 
  this 
  rock 
  proves 
  so 
  extensive 
  

   that 
  we 
  are 
  again 
  strongly 
  inclined 
  to 
  consider 
  it 
  of 
  sedimentary 
  

   origin, 
  as 
  was 
  stated 
  under 
  Whitehall. 
  

  

  In 
  the 
  southern 
  end 
  of 
  Pinnacle 
  a 
  mountain 
  the 
  gneisses 
  are 
  

   finely 
  laminated 
  garnetiferous 
  varieties 
  of 
  general 
  granitic 
  min- 
  

  

  aln 
  1898 
  the 
  remaining 
  part 
  was 
  mapped. 
  It 
  is 
  chiefly 
  gneiss, 
  of 
  the 
  same 
  general 
  

   characters 
  as 
  are 
  outlined 
  above. 
  

   bThe 
  Pinnacle 
  hill, 
  Fort 
  Ann, 
  is 
  npt 
  to 
  be 
  confused 
  with 
  "The 
  Pinnacle," 
  in 
  Granville. 
  

  

  