﻿DESCRIPTION 
  

  

  The 
  following 
  described 
  fossils 
  have 
  been 
  obtained 
  from 
  the 
  Trenton 
  

   limestone 
  since 
  the 
  publication 
  of 
  the 
  first 
  volume 
  on 
  the 
  Palaeontology 
  

   of 
  New- 
  York. 
  Several 
  of 
  these 
  are 
  entirely 
  new, 
  and 
  interesting, 
  as 
  

   adding 
  to 
  our 
  knowledge 
  of 
  several 
  genera, 
  of 
  which 
  few 
  species 
  have 
  

   yet 
  been 
  described. 
  These 
  fossils 
  were 
  collected 
  during 
  a 
  short 
  excur- 
  

   sion 
  in 
  a 
  few 
  localities 
  not 
  thoroughly 
  examined, 
  and 
  from 
  these 
  we 
  

   may 
  infer 
  that 
  a 
  large 
  number 
  yet 
  remain 
  undescribed 
  in 
  the 
  lower 
  Silu- 
  

   rian 
  rocks. 
  In 
  these 
  descriptions 
  I 
  have 
  not 
  included 
  several, 
  the 
  char- 
  

   acters 
  of 
  which 
  are 
  somewhat 
  equivocal, 
  or 
  of 
  which 
  we 
  may 
  expect 
  to 
  

   procure 
  more 
  perfect 
  specimens. 
  Several 
  specimens, 
  illustrating 
  in 
  a 
  

   more 
  perfect 
  and 
  satisfactory 
  manner 
  species 
  already 
  described 
  in 
  the 
  

   volume 
  referred 
  to, 
  have 
  been 
  added 
  to 
  this 
  list, 
  in 
  order 
  to 
  give 
  those 
  

   pursuing 
  the 
  study 
  of 
  this 
  subject 
  the 
  best 
  information 
  we 
  possess 
  up 
  to 
  

   this 
  time. 
  

  

  In 
  commencing 
  a 
  work 
  like 
  the 
  Palaeontology 
  of 
  New-York, 
  in 
  a 
  

   country 
  where 
  comparatively 
  so 
  little 
  had 
  been 
  done 
  in 
  collecting 
  or 
  in- 
  

   vestigating 
  fossils 
  of 
  the 
  older 
  rocks, 
  it 
  was 
  impossible 
  in 
  all 
  cases 
  to 
  

   procure 
  perfect 
  specimens 
  of 
  the 
  fossils 
  described. 
  It 
  is 
  expected 
  more- 
  

   over 
  that 
  the 
  fossils 
  from 
  the 
  older 
  strata 
  are 
  less 
  perfect 
  and 
  more 
  di- 
  

   lapidated 
  than 
  those 
  of 
  newer 
  formations 
  ; 
  and 
  the 
  solid 
  and 
  sometimes 
  

   altered 
  condition 
  of 
  the 
  strata 
  often 
  prevents 
  the 
  procuring 
  of 
  perfect 
  

   specimens, 
  which 
  may 
  readily 
  be 
  done 
  in 
  the 
  more 
  modern 
  formations. 
  

   It 
  would 
  not 
  be 
  satisfactory 
  to 
  the 
  student, 
  nor 
  even 
  to 
  the 
  cursory 
  ex- 
  

   aminer, 
  to 
  leave 
  unfigured 
  and 
  undescribed, 
  fragments 
  or 
  imperfect 
  

   specimens 
  of 
  fossils, 
  since 
  the 
  collection 
  of 
  every 
  one, 
  and 
  particularly 
  

   of 
  beginners, 
  must 
  necessarily 
  consist 
  in 
  part 
  of 
  such, 
  from 
  the 
  difficulty 
  

   and 
  time 
  required 
  to 
  obtain 
  perfect 
  ones. 
  It 
  is 
  therefore 
  desirable 
  from 
  

   time 
  to 
  time 
  to 
  present 
  the 
  additional 
  knowledge 
  acquired 
  by 
  the 
  fortu- 
  

  

  