﻿GEOLOGIC 
  FORMATIONS 
  OF 
  NEW 
  TOEK 
  165 
  

  

  Catskill 
  group 
  

  

  The 
  Chemung 
  passes 
  or 
  changes 
  eastward 
  into 
  the 
  Catskill, 
  an 
  

   enormous 
  series 
  of 
  shaly 
  and 
  sandy 
  strata, 
  which 
  covers 
  all 
  the 
  

   upper 
  range 
  of 
  the 
  Catskill 
  mountains, 
  and 
  many 
  of 
  the 
  higher 
  

   tracts 
  of 
  the 
  southern 
  counties 
  as 
  far 
  west 
  as 
  Steuben. 
  In 
  the 
  

   latter 
  county 
  it 
  is 
  only 
  a 
  thin 
  mass 
  of 
  calcareous 
  sandstone, 
  and 
  

   farther 
  west 
  it 
  thins 
  out 
  and 
  disappears 
  entirely; 
  but 
  in 
  the 
  Cats- 
  

   kill 
  region 
  it 
  is 
  probably 
  2,500 
  feet 
  thick, 
  and 
  twice 
  as 
  much 
  in 
  

   Pennsylvania 
  ; 
  whence 
  it 
  is 
  found 
  southward 
  along 
  the 
  mountain 
  

   ridges, 
  but 
  in 
  thinner 
  volume. 
  

  

  The 
  beds 
  of 
  this 
  series 
  are 
  varied 
  in 
  color, 
  being 
  greenish 
  gray 
  

   sandstones, 
  fine-grained 
  reddish 
  sandstones, 
  slates, 
  shales, 
  grind- 
  

   stone 
  grits 
  and 
  an 
  accretionary 
  mass 
  appearing 
  like 
  fragments 
  

   of 
  hard 
  slate 
  cemented 
  in 
  calcareous 
  rock. 
  The 
  hard 
  sandstone 
  

   often 
  weathers 
  in 
  a 
  peculiar 
  way, 
  dividing 
  into 
  thin 
  layers 
  almost 
  

   like 
  piles 
  of 
  boards. 
  ■ 
  ' 
  

  

  The 
  fossils 
  of 
  this 
  rock 
  are 
  very 
  few. 
  Recent 
  studies 
  of 
  this 
  

   group 
  suggest 
  that 
  it 
  is 
  not 
  entitled 
  to 
  distinct 
  recognition 
  but 
  is 
  

   equivalent 
  to 
  the 
  Chemung 
  and 
  perhaps 
  to 
  the 
  Portage. 
  Re- 
  

   mains 
  of 
  plants 
  are 
  numerous, 
  forming 
  occasionally 
  tiny 
  seams 
  of 
  

   coal; 
  and 
  in 
  some 
  localities 
  are 
  teeth, 
  bones 
  and 
  scales 
  of 
  fishes. 
  

   The 
  latter 
  are 
  often 
  conspicuous 
  objects, 
  as 
  they 
  are 
  usually 
  

   Avhite 
  or 
  bluish 
  in 
  color, 
  and 
  contrast 
  strongly 
  with 
  the 
  red 
  rock. 
  

  

  Life 
  of 
  the 
  Devonian 
  

  

  In 
  the 
  Devonian 
  is 
  observed 
  a 
  marked 
  general 
  advance 
  in 
  the 
  

   character 
  of 
  life 
  on 
  the 
  globe. 
  

  

  Sponges 
  were 
  few. 
  Brachiopods 
  were 
  varied 
  and 
  numerous. 
  

   Molilusks 
  were 
  abundant. 
  Corals 
  were 
  highly 
  developed 
  and 
  

   very 
  numerous. 
  I 
  > 
  

  

  Fishes 
  were 
  the 
  dominant 
  type 
  and 
  appear 
  to 
  have 
  supplanted 
  

   the 
  immense 
  cephalopods 
  which 
  ruled 
  in 
  the 
  Lower 
  Silurian 
  seas. 
  

  

  Plant 
  life 
  was 
  well 
  represented 
  on 
  land, 
  especially 
  by 
  ferns. 
  

   Conifers 
  also 
  existed. 
  

  

  The 
  abundant 
  flora 
  which 
  gave 
  rise 
  to 
  the 
  coal 
  formations 
  of 
  

   the 
  Carboniferous 
  first 
  became 
  prominent 
  in 
  the 
  Devonian. 
  

  

  