﻿3U 
  NEW 
  YORK 
  STATE 
  MUSEUM 
  

  

  A 
  table 
  of 
  analyses 
  of 
  Adirondack 
  diabases 
  has 
  been 
  recently 
  

   published 
  by 
  Kemp, 
  to 
  which 
  reference 
  may 
  be 
  made 
  by 
  such 
  as 
  

   are 
  interested 
  in 
  this 
  subject. 
  1 
  

  

  STRUCTURES 
  OF 
  THE 
  PRECAMBRIC 
  ROCKS 
  

  

  Foliation. 
  The 
  foliation 
  or 
  cleavage, 
  the 
  most 
  conspicuous 
  

   structure 
  of 
  the 
  Precambric 
  rocks, 
  is 
  found 
  in 
  sediments 
  and 
  

   igneous 
  rocks 
  alike, 
  the 
  trap 
  dikes 
  excepted. 
  But 
  the 
  sediments 
  

   are 
  better 
  foliated 
  than 
  the 
  igneous 
  rocks. 
  The 
  foliation 
  of 
  the 
  

   Grenville 
  rocks 
  of 
  the 
  Saratoga 
  region 
  is 
  parallel 
  to 
  the 
  bedding, 
  

   so 
  that 
  the 
  directions 
  of 
  the 
  two 
  are 
  equivalent. 
  This 
  seems 
  to 
  be 
  

   the 
  general 
  relation 
  of 
  the 
  two 
  in 
  the 
  Adirondacks, 
  as 
  suggested 
  

   years 
  ago 
  by 
  Van 
  Hise. 
  2 
  

  

  The 
  foliation 
  strike 
  over 
  much 
  of 
  the 
  Saratoga 
  quadrangle 
  is 
  

   nearly 
  east-west, 
  and 
  the 
  dips 
  are 
  to 
  the 
  south 
  and 
  rather 
  flat, 
  

   seldom 
  reaching 
  45 
  °. 
  The 
  strike 
  swerves 
  to 
  the 
  northwest 
  in 
  the 
  

   northeast 
  portion 
  of 
  the 
  quadrangle, 
  and 
  to 
  the 
  northeast 
  in 
  the 
  

   northwest 
  portion, 
  though 
  the 
  dips 
  remain 
  to 
  the 
  south. 
  This 
  is 
  

   not 
  in 
  accord 
  with 
  the 
  usual 
  direction 
  in 
  the 
  Adirondacks 
  where 
  

   the 
  prevailing 
  strikes 
  are 
  northeast. 
  As 
  elsewhere 
  a 
  great 
  mono- 
  

   cline 
  of 
  the 
  rocks 
  is 
  suggested; 
  and, 
  as 
  elsewhere, 
  this 
  makes 
  a 
  

   Grenville 
  succession 
  of 
  enormous 
  thickness, 
  so 
  thick 
  as 
  to 
  suggest 
  

   caution 
  in 
  interpretation 
  of 
  the 
  structure 
  and 
  as 
  to 
  emphasize 
  the 
  

   probability 
  of 
  the 
  alternative 
  suggestion 
  that 
  the 
  rocks 
  are 
  closely 
  

   pinched 
  and 
  folded, 
  in 
  a 
  series 
  of 
  closed, 
  overturned 
  folds. 
  

  

  Faults. 
  The 
  great 
  faults 
  of 
  the 
  district 
  are 
  of 
  much 
  later 
  date 
  

   than 
  the 
  Precambric, 
  and 
  dislocate 
  Precambric 
  and 
  Paleozoic 
  rocks 
  

   alike. 
  But 
  here, 
  as 
  elsewhere 
  in 
  the 
  region, 
  small 
  faults 
  are 
  noted 
  

   in 
  the 
  Precambric 
  rocks 
  of 
  such 
  character 
  that 
  they 
  seem 
  surely 
  

   of 
  Precambric 
  age. 
  We 
  have 
  found 
  as 
  yet 
  no 
  certain 
  evidence 
  of 
  

   large 
  faults 
  of 
  this 
  early 
  date. 
  

  

  PALEOZOIC 
  ROCKS 
  OF 
  THE 
  WESTERN 
  TROUGH 
  

   BY 
  H. 
  P. 
  CUSHTNG 
  

  

  The 
  terms 
  eastern 
  and 
  western 
  troughs 
  as 
  used 
  in 
  this 
  report 
  

   have 
  no 
  significance 
  other 
  than 
  convenience 
  in 
  description, 
  and 
  

   imply 
  merely 
  the 
  relative 
  positions 
  of 
  two 
  contrasted 
  sets 
  of 
  

  

  1 
  N. 
  Y. 
  State 
  Mus. 
  Bui. 
  138, 
  p. 
  60-61. 
  

  

  2 
  U. 
  S. 
  Geol. 
  Surv. 
  16th 
  Ann. 
  Rep't, 
  pt 
  1, 
  p. 
  773. 
  

  

  