﻿(2) 
  EXPLANATION 
  OF 
  PLATES. 
  

  

  The 
  ancient 
  pot-holes 
  marked 
  upon 
  the 
  eastern 
  margin 
  of 
  the 
  river 
  opposite 
  the 
  

   falls, 
  are 
  cavities 
  in 
  the 
  slate 
  filled 
  in 
  their 
  upper 
  part 
  with 
  water 
  and 
  peaty 
  mat- 
  

   ter 
  ; 
  they 
  are 
  entirely 
  similar 
  in 
  their 
  character 
  to 
  those 
  in 
  which 
  the 
  remains 
  of 
  

   Mastodon 
  were 
  found. 
  

  

  On 
  the 
  lower 
  side 
  of 
  the 
  map 
  at 
  Harmony 
  mill 
  No. 
  3, 
  is 
  shown 
  the 
  outline 
  of 
  

   the 
  pot-holes 
  in 
  which 
  the 
  mastodon 
  remains 
  were 
  found. 
  Other 
  smaller 
  pot- 
  

   holes 
  are 
  represented, 
  and 
  one 
  larger 
  one 
  to 
  the 
  east 
  of 
  the 
  mill. 
  

  

  PLATE 
  IV. 
  

  

  The 
  diagram 
  at 
  the 
  left 
  hand 
  upper 
  part 
  of 
  the 
  sheet, 
  represents 
  the 
  position 
  of 
  

   the 
  large 
  pot-hole 
  in 
  which 
  the 
  mastodon 
  remains 
  were 
  found, 
  and 
  its 
  relation 
  to 
  

   numerous 
  other 
  smaller 
  pot-holes 
  ; 
  the 
  river 
  bank 
  being 
  represented 
  on 
  the 
  right 
  

   hand 
  margin 
  of 
  the 
  sheet. 
  Several 
  of 
  the 
  smaller 
  pot-holes 
  occur 
  between 
  the 
  mill 
  

   and 
  the 
  river 
  bank, 
  and 
  others 
  on 
  the 
  east 
  side 
  and 
  beneath 
  the 
  tower. 
  Those 
  

   which 
  were 
  particularly 
  examined, 
  including 
  the 
  two 
  larger 
  ones, 
  are 
  marked 
  1 
  to 
  

   26 
  inclusive. 
  The 
  large 
  one 
  marked 
  Peat 
  bog, 
  between 
  the 
  mill 
  and 
  river 
  bank, 
  was 
  

   sufficiently 
  proved 
  by 
  excavation 
  to 
  be 
  a 
  large 
  pot-hole, 
  having 
  a 
  diameter 
  of 
  sixty- 
  

   three 
  feet. 
  In 
  digging 
  a 
  drain 
  from 
  the 
  large 
  pot-hole 
  beneath 
  the 
  mill 
  to 
  the 
  river 
  

   bank, 
  this 
  bog 
  was 
  cut 
  to 
  the 
  depth 
  of 
  ten 
  feet, 
  and 
  was 
  afterwards 
  sounded 
  by 
  

   steel 
  rods 
  to 
  a 
  farther 
  depth 
  of 
  sixteen 
  feet, 
  without 
  reaching 
  any 
  hard 
  substance. 
  

   Between 
  this 
  cavity 
  and 
  the 
  one 
  beneath 
  the 
  mill, 
  there 
  had 
  formerly 
  been 
  a 
  com- 
  

   munication 
  by 
  a 
  shallow 
  depression 
  in 
  the 
  rock. 
  

  

  The 
  line 
  indicated 
  by 
  the 
  letters 
  A 
  L 
  F 
  and 
  H, 
  marks 
  the 
  limit 
  of 
  the 
  principal 
  

   pot-hole 
  at 
  about 
  the 
  present 
  level 
  of 
  the 
  mill 
  floor. 
  The 
  dotted 
  line 
  within 
  this, 
  

   marked 
  by 
  the 
  letter 
  J, 
  indicates 
  the 
  limit 
  at 
  the 
  bottom. 
  The 
  space 
  between 
  J 
  

   and 
  H 
  is 
  occupied 
  by 
  an 
  irregular 
  slope 
  descending 
  to 
  J, 
  and 
  this 
  depression 
  at 
  

   a 
  higher 
  level, 
  extended 
  still 
  farther 
  to 
  the 
  eastward. 
  

  

  The 
  outer 
  dotted 
  line 
  represents 
  approximately 
  the 
  original 
  limits 
  of 
  a 
  swamp 
  

   with 
  a 
  central 
  pond, 
  which 
  originally 
  covered 
  the 
  openings 
  of 
  all 
  the 
  pot-holes 
  

   below. 
  

  

  The 
  pot-hole 
  beneath 
  the 
  mill, 
  marked 
  1, 
  in 
  which 
  the 
  mastodon 
  remains 
  were 
  

   principally 
  found, 
  is 
  of 
  an 
  oval 
  form, 
  its 
  greatest 
  diameter 
  being 
  in 
  a 
  line 
  nearly 
  

   east 
  by 
  north 
  and 
  west 
  by 
  south. 
  To 
  the 
  northwestward 
  it 
  communicates 
  through 
  

   a 
  deep 
  gorge 
  (between 
  the 
  points 
  B 
  and 
  G) 
  with 
  a 
  large, 
  deep 
  pot-hole, 
  No. 
  2. 
  The 
  

   points 
  of 
  rock 
  B 
  and 
  G 
  are 
  arched 
  over, 
  from 
  excavation 
  below, 
  so 
  as 
  to 
  come 
  

   within 
  a 
  few 
  feet 
  of 
  each 
  other, 
  leaving 
  the 
  opening 
  much 
  wider 
  below. 
  

  

  The 
  form 
  of 
  the 
  opening 
  and 
  the 
  measurements 
  were 
  taken 
  on 
  the 
  level 
  of 
  the 
  

   mill 
  floor 
  as 
  it 
  then 
  existed.* 
  The 
  points 
  marked 
  A 
  B 
  C 
  D, 
  are 
  those 
  upon 
  which 
  

   rest 
  the 
  arches 
  supporting 
  the 
  walls 
  of 
  the 
  building 
  above 
  these 
  cavities. 
  

  

  Dist 
  

  

  tance 
  from 
  A 
  to 
  B, 
  33 
  feet. 
  

  

  (( 
  a 
  

  

  BtoC, 
  29 
  feet. 
  

  

  t( 
  C( 
  

  

  A 
  to 
  0, 
  62 
  feet. 
  

  

  it 
  a 
  

  

  L 
  to 
  H, 
  73 
  feet. 
  

  

  (( 
  ct 
  

  

  F 
  to 
  Fi, 
  38 
  feet. 
  

  

  C( 
  (( 
  

  

  i 
  to 
  k, 
  171 
  feet. 
  

  

  The 
  rock 
  marked 
  Table 
  is 
  a 
  large 
  mass 
  of 
  slate, 
  12 
  X 
  18 
  to 
  20 
  feet 
  across 
  the 
  

   * 
  The 
  surface 
  of 
  the 
  rock 
  was 
  afterwards 
  lowered 
  by 
  excavation 
  about 
  eighteen 
  inches. 
  

  

  