﻿EXPLANATION 
  OF 
  PLATES. 
  (3) 
  

  

  surface, 
  which 
  is 
  eight 
  to 
  ten 
  feet 
  below 
  the 
  level 
  of 
  the 
  floor 
  of 
  the 
  building. 
  

   This 
  rock, 
  on 
  its 
  upper 
  face, 
  presents 
  the 
  limits 
  marked 
  by 
  the 
  continuous 
  line, 
  

   sloping 
  a 
  little 
  towards 
  F, 
  where 
  it 
  is 
  two 
  feet 
  lower 
  than 
  on 
  the 
  opposite 
  side. 
  

   The 
  northerly 
  face 
  of 
  this 
  mass 
  is 
  nearly 
  vertical, 
  the 
  top 
  being 
  slightly 
  overhang- 
  

   ing; 
  the 
  easterly 
  face 
  is 
  also 
  essentially 
  vertical. 
  On 
  the 
  southerly 
  and 
  south- 
  

   westerly 
  faces 
  the 
  surfaces 
  are 
  sloping 
  downward 
  to 
  the 
  limit 
  indicated 
  by 
  the 
  

   dotted 
  line. 
  

  

  Near 
  the 
  base 
  of 
  this 
  mass 
  there 
  is 
  a 
  regular 
  even 
  line 
  of 
  fracture, 
  or 
  natural 
  

   jointing, 
  along 
  which 
  the 
  mass 
  has 
  apparently 
  slipped 
  for 
  a 
  distance 
  of 
  about 
  one 
  

   foot 
  to 
  the 
  southeastward, 
  since 
  the 
  formation 
  of 
  the 
  pot-hole, 
  leaving 
  the 
  base 
  

   projecting 
  at 
  b, 
  as 
  shown 
  in 
  the 
  accompanying 
  wood 
  cut, 
  fig. 
  1, 
  which 
  represents 
  a 
  

   transverse 
  section 
  of 
  the 
  principal 
  cavity 
  along 
  the 
  face 
  of 
  the 
  table 
  rock 
  from 
  F 
  

   to 
  Fi. 
  

  

  The 
  point 
  marked 
  G 
  is 
  at 
  about 
  the 
  same 
  level 
  as 
  the 
  central 
  table 
  rock, 
  the 
  arc 
  

   indicating 
  that 
  it 
  has 
  at 
  one 
  time 
  formed 
  a 
  part 
  of 
  the 
  bottom 
  of 
  a 
  pot-hole, 
  grad- 
  

   ually 
  curving 
  upwards 
  to 
  within 
  two 
  and 
  a 
  half 
  feet 
  of 
  the 
  floor 
  level, 
  with 
  the 
  

   margin 
  perpendicular. 
  At 
  E 
  there 
  is 
  a 
  narrow 
  passage, 
  measuring 
  twelve 
  feet 
  

   from 
  g 
  to 
  h 
  y 
  which 
  is 
  filled 
  up 
  by 
  a 
  large 
  mass 
  of 
  the 
  slate 
  rock. 
  This 
  has 
  ap- 
  

   parently 
  been 
  pushed 
  forward 
  from 
  above, 
  or 
  fallen 
  into 
  the 
  gorge 
  at 
  a 
  former 
  

   period. 
  Beyond 
  the 
  slaty 
  mass 
  the 
  channel 
  is 
  filled 
  with 
  loose 
  earth 
  and 
  other 
  

   foreign 
  materials. 
  This 
  channel 
  is 
  probably 
  the 
  course 
  by 
  which 
  the 
  water 
  entered 
  

   the 
  larger 
  excavations 
  to 
  the 
  southward. 
  

  

  The 
  larger 
  cavity 
  is 
  deepest 
  at 
  F, 
  though 
  the 
  entire 
  depth 
  is 
  unknown. 
  Within 
  

   the 
  outer 
  dotted 
  line 
  there 
  are 
  several 
  smaller 
  pot-holes, 
  marked 
  6, 
  7 
  and 
  8. 
  No. 
  

   6 
  is 
  nine 
  feet 
  ten 
  inches 
  in 
  diameter, 
  the 
  depth 
  not 
  ascertained. 
  No. 
  7 
  is 
  ten 
  by 
  

   twelve 
  and 
  a 
  half 
  feet 
  in 
  diameter. 
  No. 
  8 
  represents 
  two 
  small 
  pot-holes, 
  worn 
  

   into 
  each 
  other 
  at 
  their 
  adjacent 
  margins. 
  

  

  In 
  the 
  tower, 
  140 
  feet 
  from 
  the 
  north 
  wall, 
  there 
  are 
  evidences 
  of 
  eight 
  other 
  

   pot-holes, 
  of 
  various 
  sizes. 
  No. 
  10 
  is 
  represented 
  in 
  section 
  (Fig. 
  2 
  of 
  diagram), 
  

   as 
  described 
  by 
  Mr. 
  Houlihan, 
  superintendent 
  of 
  the 
  work. 
  

  

  The 
  points 
  marked 
  by 
  horizontal 
  lines 
  represent 
  the 
  places 
  at 
  which 
  parts 
  of 
  the 
  

   mastodon 
  skeleton 
  were 
  found, 
  a 
  being 
  the 
  point 
  where 
  the 
  lower 
  jaw 
  and 
  one 
  of 
  

   the 
  phalanges 
  of 
  the 
  left 
  fore 
  foot 
  were 
  found 
  ; 
  6, 
  the 
  place 
  of 
  the 
  skull, 
  most 
  of 
  

   the 
  vertebrae 
  and 
  ribs, 
  the 
  pelvis, 
  scapula, 
  leg 
  and 
  foot 
  bones, 
  etc. 
  ; 
  c, 
  one 
  of 
  the 
  

   vertebrae 
  ; 
  d, 
  place 
  of 
  one 
  of 
  the 
  anterior 
  ribs 
  ; 
  e, 
  place 
  of 
  a 
  rib. 
  At 
  /, 
  in 
  pot 
  hole 
  

   No. 
  3, 
  the 
  bones 
  of 
  the 
  right 
  fore 
  leg 
  were 
  found 
  at 
  about 
  sixty 
  feet 
  distant 
  from 
  

   the 
  place 
  of 
  the 
  skull 
  and 
  other 
  bones. 
  

  

  Fig. 
  2. 
  — 
  Section 
  of 
  pot-hole 
  No. 
  10, 
  at 
  the 
  angle 
  of 
  the 
  tower. 
  

  

  This 
  pot-hole 
  is 
  narrow 
  above, 
  having 
  a 
  depth 
  of 
  nineteen 
  feet 
  six 
  inches. 
  The 
  

   diameter 
  at 
  the 
  top 
  is 
  sixteen 
  inches, 
  and 
  in 
  the 
  widest 
  part 
  eight 
  feet. 
  At 
  the 
  first 
  

   contraction 
  below 
  the 
  centre 
  it 
  has 
  a 
  diameter 
  of 
  two 
  feet, 
  and 
  at 
  the 
  lower 
  one 
  the 
  

   diameter 
  is 
  but 
  six 
  inches. 
  It 
  was 
  originally 
  filled 
  with 
  water-worn 
  gravel, 
  to 
  the 
  

   height 
  of 
  the 
  dotted 
  line. 
  

  

  Fig. 
  3. 
  — 
  A 
  section 
  across 
  the 
  river-bed, 
  from 
  north 
  to 
  south 
  (N. 
  S.). 
  a 
  repre- 
  

   sents 
  the 
  gravel 
  hills 
  underlaid 
  by 
  clay 
  ; 
  b, 
  the 
  Erie 
  canal 
  ; 
  c 
  and 
  d 
  are 
  raceways, 
  

   excavated 
  in 
  the 
  slate 
  rock, 
  for 
  carrying 
  water 
  to 
  the 
  mills 
  ; 
  e, 
  the 
  new 
  Harmony 
  

   mill 
  ; 
  /, 
  dwelling-houses 
  on 
  the 
  summit 
  of 
  the 
  river 
  bank 
  ; 
  g, 
  top 
  of 
  river 
  bank 
  

   before 
  excavation, 
  which 
  is 
  106 
  feet 
  above 
  the 
  level 
  of 
  the 
  river-bed 
  ; 
  g 
  rep- 
  

   resents 
  the 
  level 
  of 
  the 
  mill-yard 
  ; 
  h, 
  level 
  of 
  the 
  water 
  in 
  river-bed 
  at 
  ordinary 
  

   stage. 
  During 
  the 
  dry 
  season 
  the 
  water 
  is 
  confined 
  to 
  the 
  narrow 
  channel 
  below 
  

  

  