﻿COHOES 
  MASTODON. 
  

  

  135 
  

  

  Fig. 
  7. 
  

  

  water 
  line.* 
  For 
  a 
  space 
  of 
  five 
  rods 
  above 
  and 
  as 
  much 
  below 
  

   the 
  fall 
  there 
  is 
  no 
  vegetation; 
  the 
  weight 
  of 
  frozen 
  spray 
  may 
  

   have 
  uprooted 
  such 
  plants 
  as 
  have 
  obtained 
  foot-hold. 
  From 
  the 
  

   upper 
  limit 
  of 
  this 
  barren 
  space 
  to 
  a 
  promontory 
  500 
  feet 
  further 
  up, 
  

   the 
  existing 
  plants 
  are 
  dwarfed, 
  contorted 
  cedars, 
  appearing 
  at 
  a 
  

  

  little 
  distance 
  mere 
  bushes, 
  

   but 
  really 
  very 
  old 
  trees. 
  The 
  

   roots 
  crowd 
  into 
  the 
  crevices 
  

   of 
  the 
  shale 
  without 
  any 
  soil; 
  

   and, 
  without 
  exception, 
  have 
  

   been 
  partially 
  bared 
  by 
  the 
  

   waste 
  of 
  the 
  cliff 
  during 
  the 
  

   growth 
  of 
  the 
  trees. 
  The 
  

   older 
  trees 
  hang 
  by 
  long 
  roots 
  

   from 
  points 
  of 
  support 
  often 
  

   above 
  their 
  highest 
  branches, 
  

   and 
  are 
  much 
  contorted 
  and 
  

   scarred 
  (fig. 
  7). 
  Climbing 
  

   from 
  below, 
  or 
  lowered 
  by 
  a 
  

   rope 
  from 
  above, 
  I 
  have 
  ex- 
  

   amined 
  nearly 
  all 
  these 
  trees, 
  

   and 
  measured 
  in 
  each 
  case 
  the 
  

   circumference 
  of 
  trunk 
  and 
  

   length 
  of 
  exposed 
  root. 
  I 
  

   have 
  also 
  counted 
  the 
  rings 
  of 
  annual 
  accretion 
  of 
  several 
  sections 
  

   to 
  ascertain 
  the 
  relation 
  of 
  size 
  to 
  acre. 
  From 
  these 
  data 
  an 
  idea 
  

   may 
  be 
  obtained 
  of 
  the 
  rate 
  of 
  recession 
  of 
  the 
  cliff. 
  The 
  growth 
  

   is 
  exceedingly 
  slow. 
  A 
  branch 
  of 
  one 
  and 
  one-eighth 
  inch 
  in 
  

   diameter 
  showed 
  100 
  rings 
  of 
  growth, 
  and 
  an 
  average 
  of 
  six 
  such 
  

   branches 
  gave 
  72 
  years 
  per 
  inch 
  of 
  diameter. 
  The 
  figures 
  used 
  

   below 
  were 
  obtained 
  from 
  two 
  sections 
  of 
  trunks. 
  One 
  of 
  these 
  

   (specimen 
  preserved) 
  measures 
  19^ 
  inches 
  in 
  circumference, 
  and 
  

   exhibits 
  310 
  rings 
  ; 
  the 
  other 
  gave 
  11 
  inches 
  and 
  270 
  rings. 
  In 
  

   these 
  an 
  inch 
  of 
  circumference 
  represents 
  19.1 
  years, 
  and 
  an 
  inch 
  

   of 
  diameter, 
  60 
  years. 
  

  

  * 
  See 
  note 
  A. 
  

  

  