﻿198 
  NEW 
  YORK 
  STATE 
  MUSEUM 
  

  

  less 
  crystalline 
  texture. 
  There 
  is 
  however 
  some 
  confusion 
  in 
  the 
  

   use 
  of 
  the 
  terms, 
  and 
  the 
  same 
  stone 
  is 
  occasionally 
  known 
  as 
  

   marble 
  and 
  limestone, 
  e. 
  g., 
  the 
  Lockport 
  limestone 
  or 
  marble; 
  

   the 
  limestone 
  and 
  coral 
  shell 
  marble 
  of 
  Becraft's 
  mountain, 
  near 
  

   Hudson; 
  the 
  Lepanto 
  marble 
  or 
  limestone 
  near 
  Plattsburg, 
  and 
  

   others. 
  

  

  The 
  fossiliferous 
  limestones 
  are 
  made 
  up 
  of 
  the 
  remains 
  of 
  

   organisms 
  which 
  have 
  grown 
  in 
  situ, 
  as 
  for 
  example, 
  the 
  coralline 
  

   beds 
  in 
  the 
  Helderberg 
  and 
  Niagara 
  limestones, 
  or 
  have 
  been 
  

   deposited 
  as 
  marine 
  sediments. 
  In 
  the 
  case 
  of 
  the 
  latter 
  the 
  

   fossils 
  are 
  more 
  or 
  less 
  comminuted 
  and 
  held 
  in 
  a 
  calcareous 
  

   matrix. 
  Generally 
  the 
  fossil 
  portions 
  of 
  the 
  mass 
  are 
  crystalline. 
  

   The 
  Onondaga 
  gray 
  limestone 
  from 
  near 
  Syracuse, 
  and 
  the 
  Lock- 
  

   port 
  encrinal 
  limestone 
  are 
  good 
  examples. 
  

  

  The 
  fossil 
  remains 
  are 
  less 
  prominent 
  and 
  scarcely 
  visible 
  in 
  

   some 
  of 
  the 
  common 
  blue 
  limestones, 
  as 
  in 
  the 
  lower 
  beds 
  of 
  

   Calciferous 
  and 
  in 
  some 
  of 
  the 
  Helderberg 
  series. 
  These 
  rocks 
  

   are 
  compact, 
  homogeneous 
  and 
  apparently 
  uncrystalline 
  and 
  un- 
  

   f 
  ossilif 
  erous. 
  They 
  are 
  usually 
  more 
  siliclous 
  or 
  argillaceous, 
  that 
  

   is, 
  they 
  contain 
  quartz 
  or 
  clay, 
  the 
  latter 
  o:§ten 
  in 
  seams 
  rudely 
  

   parallel 
  with 
  the 
  bedding 
  planes. 
  On 
  weathering, 
  the 
  difference 
  

   in 
  composition 
  is 
  often 
  markedly 
  apparent 
  at 
  a 
  glance. 
  Similar 
  

   differences 
  in 
  composition 
  are 
  seen 
  in 
  the 
  more 
  crystalline 
  mar- 
  

   bles, 
  and 
  are 
  evident 
  either 
  by 
  variation 
  in 
  color, 
  or 
  in 
  the 
  pres- 
  

   ence 
  of 
  foreign 
  minerals, 
  as 
  mica, 
  quartz, 
  hornblende, 
  pyrite, 
  etc. 
  

  

  The 
  variations 
  in 
  the 
  strength 
  and 
  durability 
  is 
  as 
  great 
  as 
  in 
  

   the 
  composition 
  and 
  texture. 
  Some 
  are 
  stronger 
  than 
  many 
  

   granites 
  in 
  their 
  resistance 
  to 
  crushing 
  force, 
  and 
  equally 
  endur- 
  

   ing; 
  others 
  consist 
  of 
  loosely 
  cohering 
  grains, 
  and 
  are 
  friable 
  and 
  

   rapidly 
  dissolved 
  by 
  atmospheric 
  agencies. 
  The 
  more 
  silicious 
  

   and 
  compact 
  limestones 
  are 
  generally 
  the 
  more 
  durable 
  and 
  

   stronger; 
  in 
  the 
  marble 
  the 
  well-crystallized 
  and 
  more 
  homogene- 
  

   ous 
  texture 
  consists 
  with 
  endurance 
  and 
  strength. 
  Both 
  the 
  mag- 
  

   nesian 
  and 
  dolomitic 
  varieties 
  are 
  good 
  stone 
  as 
  is 
  proven 
  by 
  the 
  

   Calciferous 
  and 
  the 
  Niagara 
  limestones, 
  and 
  in 
  the 
  marbles 
  of 
  

   Tuckahoe 
  and 
  Pleasantville, 
  in 
  Westchester 
  county. 
  

  

  