﻿158 
  NEW 
  YORK 
  STATE 
  MUSEUM 
  

  

  before 
  the 
  slip. 
  The 
  ultimate 
  source 
  of 
  strain 
  which 
  gave 
  rise 
  

   to 
  the 
  fissuring 
  rnay 
  be 
  found 
  in 
  a 
  possible 
  undermining 
  of 
  the 
  

   upper 
  beds 
  by 
  underground 
  flowage. 
  

  

  The 
  pressure 
  exerted 
  by 
  the 
  fall 
  of 
  the 
  block 
  was 
  communicated 
  

   by 
  the 
  semiliquid 
  clay 
  to 
  the 
  beds 
  next 
  to 
  the 
  stream 
  which 
  were 
  

   raised 
  up 
  and 
  shoved 
  a 
  few 
  feet 
  to 
  the 
  south. 
  The 
  volume 
  of 
  

   the 
  displacement 
  was 
  estimated 
  roughly 
  at 
  between 
  4000 
  and 
  500a 
  

   cubic 
  yards. 
  

  

  There 
  can 
  be 
  little 
  basis 
  for 
  connecting 
  the 
  slip 
  with 
  a 
  move- 
  

   ment 
  in 
  the 
  underlying 
  Hudson 
  River 
  shales, 
  though 
  such 
  a 
  rela- 
  

   tion 
  might 
  be 
  suggested 
  by 
  the 
  known 
  occurrences 
  of 
  postglacial 
  

   faulting 
  in 
  the 
  region. 
  A 
  rock 
  fault 
  at 
  all 
  commensurate 
  to 
  that 
  

   observed 
  at 
  the 
  "surface 
  would 
  have 
  had 
  far-reaching 
  effects, 
  and 
  

   even 
  a 
  slight 
  dislocation, 
  such 
  as 
  would 
  supply 
  merely 
  an 
  impulse 
  

   in 
  precipitating 
  the 
  mass 
  of 
  clay 
  already 
  in 
  delicate 
  equilibrium, 
  

   could 
  scarcely 
  have 
  happened, 
  for 
  it 
  would 
  have 
  been 
  accompanied 
  

   by 
  earth 
  tremors 
  of 
  sufficient 
  magnitude 
  at 
  least 
  to 
  have 
  been 
  

   detected 
  by 
  the 
  seismograph 
  at 
  Albany. 
  

  

  In 
  this 
  connection 
  it 
  may 
  be 
  noted 
  that 
  the 
  slip 
  occurred 
  within 
  

   a 
  short 
  time 
  after 
  the 
  heavy 
  earthquake 
  of 
  March 
  26th 
  in 
  southern 
  

   Mexico. 
  The 
  transmitted 
  vibrations 
  from 
  the 
  earthquake 
  were 
  

   registered 
  at 
  Albany 
  beginning 
  at 
  6.10 
  p. 
  m. 
  Though 
  they 
  were 
  

   of 
  exceptional 
  magnitude, 
  it 
  would 
  hardly 
  seem 
  justifiable 
  to 
  infer 
  

   any 
  direct 
  relation 
  between 
  the 
  two 
  phenomena. 
  

  

  The 
  writer 
  is 
  indebted 
  to 
  Mr 
  H. 
  P. 
  Whitlock 
  for 
  the 
  accom- 
  

   panying 
  illustrations 
  and 
  to 
  Mr 
  C. 
  R. 
  Van 
  de 
  Carr, 
  on 
  whose 
  prop- 
  

   erty 
  the 
  landslip 
  occurred, 
  for 
  information 
  and 
  courtesies 
  extended 
  

   during 
  his 
  visit 
  to 
  the 
  locality. 
  

  

  