﻿GEOLOGY 
  OF 
  THE 
  NORTH 
  CREEK 
  QUADRANGLE 
  43 
  

  

  1 
  From 
  western 
  base 
  of 
  Heath 
  mountain, 
  North 
  Creek 
  sheet, 
  Warren 
  

   county. 
  Analyst 
  Morley. 
  

  

  2 
  From 
  summit 
  of 
  Mt 
  Marcy, 
  Essex 
  county. 
  Analyst 
  Leeds. 
  N. 
  Y. 
  State 
  

   Mus. 
  30th 
  Annual 
  Rep't, 
  p. 
  102. 
  

  

  3 
  From 
  shore 
  of 
  Upper 
  Chateaugay 
  lake, 
  Clinton 
  county. 
  Analyst 
  Eakle. 
  

   Amer. 
  Geol. 
  July 
  1893, 
  p. 
  35. 
  

  

  4 
  From 
  Palmer 
  Hill, 
  Black 
  Brook 
  township, 
  Clinton 
  county. 
  x\nalyst 
  

   Kemp. 
  U. 
  S. 
  Geol. 
  Surv. 
  Bui. 
  107, 
  p. 
  26. 
  

  

  5 
  From 
  Bellmont 
  township, 
  Franklin 
  county, 
  dike 
  13. 
  Analyst 
  Morley. 
  

   N. 
  Y. 
  State 
  Geol. 
  18th 
  Annual 
  Rep't, 
  p. 
  120. 
  

  

  6 
  From 
  shore 
  of 
  Upper 
  Chateaugay 
  lake, 
  Clinton 
  county. 
  Analyst 
  Eakle. 
  

   Op. 
  tit., 
  p. 
  35- 
  

  

  The 
  North 
  Creek 
  sheet 
  diabase 
  (no. 
  i) 
  is 
  lower 
  in 
  Al 
  2 
  O 
  s 
  and 
  

   CaO, 
  and 
  higher 
  in 
  Ti0 
  2 
  than 
  any 
  of 
  the 
  others. 
  It 
  is 
  also 
  some- 
  

   what 
  more 
  acid 
  than 
  usual 
  for 
  the 
  diabases, 
  due 
  to 
  the 
  more 
  acid 
  

   character 
  of 
  the 
  plagioclase 
  feldspar. 
  

  

  Lack 
  of 
  variation 
  of 
  the 
  diabase 
  

   Because 
  of 
  its 
  remarkable 
  homogeneity 
  in 
  composition, 
  the 
  dia- 
  

   base 
  presents 
  a 
  marked 
  contrast 
  to 
  the 
  neighboring 
  gabbro. 
  The 
  

   diabase 
  never 
  contains 
  inclusions 
  and, 
  with 
  a 
  single 
  very 
  local 
  ex- 
  

   ception 
  below 
  described, 
  never 
  shows 
  any 
  evidence 
  of 
  magmatic 
  

   assimilation 
  even 
  in 
  the 
  largest 
  masses. 
  This 
  difference 
  is 
  quite 
  

   certainly 
  due 
  to 
  the 
  difference 
  in 
  the 
  mode 
  and 
  condition 
  of 
  intru- 
  

   sion, 
  the 
  diabase 
  having 
  clearly 
  been 
  forced 
  through 
  comparatively 
  

   narrow 
  fissures 
  in 
  the 
  country 
  rock 
  and 
  near 
  the 
  earth's 
  surface 
  as 
  

   the 
  texture 
  shows. 
  In 
  such 
  intrusions 
  magmatic 
  stoping 
  would 
  be 
  

   reduced 
  to 
  a 
  minimum 
  or 
  absent. 
  

  

  Contact 
  phenomena 
  

  

  A 
  small 
  dike, 
  $y 
  2 
  inches 
  wide, 
  which 
  cuts 
  the 
  Grenville 
  limestone 
  

   at 
  the 
  asbestos 
  mine 
  three-quarters 
  of 
  a 
  mile 
  southeast 
  of 
  Thur- 
  

   man, 
  shows 
  contact 
  phenomena 
  which 
  deserve 
  special 
  mention. 
  Fol- 
  

   lowing 
  is 
  a 
  description 
  based 
  upon 
  thin 
  sections 
  and 
  hand 
  specimens 
  

   (see 
  plate 
  7). 
  

  

  Zone 
  1 
  This 
  is 
  typical, 
  unaltered, 
  medium 
  grained, 
  greenish 
  gray, 
  

   serpentine 
  marble. 
  

  

  Zone 
  2 
  This 
  zone, 
  about 
  one-third 
  of 
  an 
  inch 
  wide, 
  lies 
  along 
  the 
  

   contact 
  with 
  the 
  diabase. 
  It 
  consists 
  of 
  a 
  fine 
  grained, 
  dark 
  green, 
  

   well-baked 
  serpentine 
  marble. 
  

  

  Zone 
  3 
  One-sixth 
  of 
  an 
  inch 
  wide. 
  Nearly 
  black 
  (greenish 
  

   gray 
  in 
  thin 
  section), 
  glassy 
  looking 
  dike 
  rock 
  which 
  shows 
  an 
  irreg- 
  

   ular 
  but 
  sharp 
  boundary 
  against 
  the 
  marble. 
  It 
  appears 
  to 
  consist 
  

  

  