﻿GEOLOGY 
  OF 
  THE 
  NORTH 
  CREEK 
  QUADRANGLE 
  2$ 
  

  

  gray, 
  medium-grained, 
  biotitic, 
  granitic 
  gneiss 
  which 
  is 
  intimately 
  

   associated 
  with 
  some 
  Grenville 
  gneiss. 
  Here 
  again 
  it 
  is 
  quite 
  cer- 
  

   tain 
  that 
  the 
  granitic 
  gneiss 
  forms 
  a 
  border 
  zone 
  between 
  the 
  gran- 
  

   ite 
  porphyry 
  and 
  the 
  Grenville, 
  where 
  the 
  former 
  has 
  more 
  or 
  less 
  

   assimilated 
  some 
  of 
  the 
  latter. 
  

  

  Along 
  the 
  southeastern 
  base 
  of 
  Moon 
  mountain 
  there 
  are 
  excel- 
  

   lent 
  exposures 
  of 
  Grenville 
  much 
  cut 
  up 
  by, 
  and 
  often 
  fused 
  into, 
  

   syenite. 
  

  

  The 
  mixed 
  gneiss 
  area 
  at 
  the 
  southwestern 
  corner 
  of 
  the 
  map 
  

   affords 
  many 
  fine 
  examples 
  of 
  syenite 
  or 
  granite 
  and 
  Grenville 
  

   closely 
  involved 
  and 
  fused 
  together. 
  There 
  are 
  also 
  many 
  well- 
  

   defined 
  inclusions 
  or 
  stringers 
  of 
  Grenville 
  scattered 
  through 
  the 
  

   igenous 
  rock. 
  These 
  phenomena 
  are 
  especially 
  well 
  shown 
  on 
  Wolf 
  

   Pond 
  mountain. 
  

  

  The 
  mixed 
  gneiss 
  area 
  which 
  surrounds 
  Heath 
  mountain 
  con- 
  

   sists 
  very 
  largely 
  of 
  Grenville 
  gneisses 
  and 
  limestones 
  through 
  

   which 
  numerous 
  small 
  masses 
  of 
  syenite 
  or 
  granite 
  have 
  been 
  in- 
  

   truded. 
  The 
  most 
  interesting 
  exposures 
  occur 
  along 
  the 
  river 
  

   for 
  nearly 
  a 
  mile 
  northward 
  from 
  the 
  Ferry. 
  About 
  I 
  mile 
  north 
  

   of 
  the 
  Ferry 
  and 
  on 
  the 
  east 
  side 
  of 
  the 
  river, 
  are 
  great 
  ledges 
  

   of 
  Grenville 
  limestone 
  and 
  hornblende 
  gneiss, 
  these 
  rocks 
  being 
  

   badly 
  contorted 
  and 
  broken 
  and 
  containing 
  some 
  patches 
  of 
  good 
  

   syenite, 
  10 
  to 
  30 
  feet 
  across, 
  and 
  completely 
  surrounded 
  by 
  either 
  

   hornblende 
  gneiss 
  or 
  marble. 
  At 
  the 
  same 
  locality 
  a 
  large 
  mass 
  of 
  

   syenite 
  overlies 
  crystalline 
  limestone 
  and 
  shows 
  the 
  actual 
  sharp 
  

   contact 
  for 
  fully 
  100 
  feet, 
  there 
  being 
  no 
  particular 
  contact 
  

   phenomena 
  (see 
  plate 
  3). 
  

  

  About 
  one-half 
  of 
  a 
  mile 
  north 
  of 
  the 
  Ferry, 
  and 
  along 
  the 
  road, 
  

   there 
  are 
  several 
  very 
  interesting 
  inclusions 
  of 
  Grenville 
  limestone 
  

   in 
  the 
  syenite. 
  Two 
  of 
  these 
  inclusions 
  (one 
  being 
  3 
  or 
  4 
  feet 
  

   across 
  and 
  the 
  other 
  20 
  feet 
  long 
  and 
  2 
  to 
  4 
  feet 
  wide) 
  are 
  com- 
  

   pletely 
  surrounded 
  by, 
  and 
  in 
  very 
  sharp 
  contact 
  with, 
  the 
  syenite. 
  

   The 
  limestone 
  is 
  coarse, 
  crystalline, 
  calcitic, 
  and 
  contains 
  graphite. 
  

   At 
  the 
  contacts 
  small 
  green 
  pyroxene 
  crystals 
  are 
  often 
  common. 
  

  

  The 
  small 
  area 
  near 
  Daggett 
  pond 
  is 
  of 
  interest 
  because 
  the 
  

   Grenville 
  is 
  there 
  interbanded 
  with 
  granitic 
  syenite, 
  the 
  bands 
  of 
  

   each 
  rock 
  often 
  being 
  20 
  to 
  40 
  feet 
  wide 
  and 
  the 
  contacts 
  pretty 
  

   sharp. 
  One 
  Grenville 
  band 
  is 
  a 
  garnet, 
  pyroxene 
  gneiss, 
  while 
  

   others 
  are 
  biotite 
  or 
  hornblende 
  gneisses. 
  

  

  The 
  area 
  of 
  mixed 
  gneisses 
  lying 
  to 
  the 
  east 
  of 
  Stockton 
  and 
  

   Gage 
  mountains 
  shows 
  numerous 
  exposures 
  of 
  closely 
  associated 
  

  

  