﻿1 
  8 
  NEW 
  YORK 
  STATE 
  MUSEUM 
  

  

  plateau 
  and 
  Mohawk 
  valley 
  provinces 
  where 
  the 
  hard 
  limestone 
  

   lies 
  at 
  an 
  altitude 
  of 
  more 
  than 
  iooo 
  feet, 
  and 
  directly 
  overlies 
  the 
  

   soft 
  shales 
  of 
  the 
  valley 
  whose 
  altitude 
  is 
  only 
  a 
  few 
  hundred 
  feet. 
  

  

  CATSKILL 
  MOUNTAIN 
  PROVINCE 
  

  

  This 
  is 
  the 
  most 
  rugged 
  of 
  all 
  provinces 
  in 
  the 
  State 
  and, 
  next 
  

   to 
  the 
  Adirondacks, 
  contains 
  the 
  greatest 
  elevations. 
  Slide 
  moun- 
  

   tain 
  (4205 
  feet) 
  is 
  the 
  highest, 
  while 
  a 
  number 
  of 
  points 
  range 
  

   from 
  3500 
  to 
  over 
  4000 
  feet 
  in 
  altitude. 
  

  

  The 
  rocks 
  are 
  all 
  of 
  Devonic 
  age 
  and 
  consist 
  almost 
  entirely 
  of 
  

   sandstones 
  and 
  conglomerates. 
  Except 
  for 
  a 
  slight 
  westward 
  un- 
  

   dulation, 
  these 
  rocks 
  are 
  arranged 
  in 
  practically 
  horizontal 
  layers 
  and 
  

   show 
  an 
  aggregate 
  thickness 
  of 
  several 
  thousand 
  feet 
  (see 
  figure 
  6). 
  

   Lying 
  under 
  these 
  Devonic 
  rocks 
  and 
  outcropping 
  at 
  the 
  very 
  base 
  

   of 
  the 
  mountains 
  on 
  the 
  north 
  and 
  east, 
  are 
  various 
  formations 
  of 
  

   Siluric 
  age. 
  

  

  The 
  term 
  " 
  mountains 
  " 
  as 
  applied 
  to 
  the 
  Catskills 
  requires 
  some 
  

   explanation. 
  The 
  more 
  typical 
  mountains 
  of 
  the 
  world 
  have 
  been 
  

   formed 
  by 
  folding 
  or 
  faulting 
  of 
  the 
  strata, 
  or 
  by 
  igneous 
  activity, 
  

   or 
  by 
  two 
  or 
  all 
  of 
  these 
  causes 
  combined. 
  For 
  example, 
  in 
  the 
  

   development 
  of 
  the 
  Appalachians 
  both 
  folding 
  and 
  faulting 
  have 
  

   played 
  prominent 
  parts, 
  while 
  in 
  mountains 
  like 
  the 
  Sierras 
  or 
  

   Adirondacks, 
  folding, 
  faulting, 
  and 
  igneous 
  action 
  have 
  all 
  been 
  

   important. 
  The 
  Catskills, 
  however, 
  in 
  which 
  these 
  typical 
  moun- 
  

   tain 
  phenomena 
  are 
  wholly 
  lacking, 
  are 
  to 
  be 
  properly 
  placed 
  in 
  

   the 
  category 
  of 
  what 
  we 
  may 
  call 
  " 
  erosion 
  mountains." 
  Moun- 
  

   tains 
  of 
  the 
  pure 
  erosion 
  type 
  are 
  due 
  to 
  an 
  uplift 
  of 
  land 
  high 
  

   above 
  sea 
  level, 
  followed 
  by 
  deep 
  dissection 
  of 
  the 
  elevated 
  mass 
  

   by 
  the 
  action 
  of 
  streams. 
  The 
  Catskills 
  are 
  only 
  an 
  easterly 
  ex- 
  

   tension 
  of 
  the 
  plateau 
  province 
  where 
  the 
  rocks 
  are 
  more 
  resistant 
  

   and 
  perhaps 
  the 
  elevation 
  of 
  the 
  region 
  was 
  greater, 
  so 
  that 
  the 
  

   streams 
  were 
  able 
  to 
  cut 
  deeper 
  trenches 
  while 
  the 
  harder 
  rocks 
  of 
  

   the 
  divides 
  have 
  so 
  far 
  prevented 
  a 
  general 
  wearing 
  down 
  of 
  the 
  

   region. 
  The 
  Catskills 
  furnish 
  a 
  remarkable 
  example 
  of 
  a 
  high 
  

   plateau 
  deeply 
  dissected 
  by 
  numerous 
  streams. 
  The 
  whole 
  topog- 
  

   raphy 
  is 
  very 
  rugged, 
  all 
  being 
  much 
  like 
  that 
  of 
  the 
  highest 
  por- 
  

   tion 
  of 
  the 
  Adirondacks 
  around 
  Mount 
  Marcy 
  (compare 
  plates 
  

   2 
  and 
  5). 
  The 
  Catskills, 
  however, 
  lacking 
  the 
  proper 
  structural 
  

   features, 
  show 
  practically 
  no 
  tendency 
  to 
  parallel 
  arrangement 
  of 
  

   ridges 
  or 
  mountains 
  as 
  is 
  so 
  common 
  in 
  the 
  Adirondacks. 
  

  

  On 
  the 
  south 
  the 
  Catskill 
  province 
  almost 
  grades 
  into 
  the 
  folded 
  

   region 
  of 
  the 
  Appalachians, 
  while 
  on 
  the 
  west 
  it 
  gradually 
  merges 
  

   into 
  the 
  southwestern 
  plateau. 
  On 
  the 
  north 
  the 
  Helderberg 
  

  

  