﻿No. 
  30.] 
  

  

  77 
  

  

  From 
  William 
  H. 
  Grant, 
  of 
  Barrytown, 
  New- 
  York. 
  

  

  Seven 
  Lenticular 
  concretions. 
  From 
  the 
  black 
  shale 
  of 
  the 
  

   Hudson 
  River 
  group, 
  quarried 
  out 
  in 
  making 
  excava- 
  

   tions 
  for 
  the 
  track 
  of 
  the 
  Hudson 
  river 
  railroad, 
  about 
  

   four 
  miles 
  north 
  of 
  Stuyvesant 
  Landing, 
  Columbia 
  

   county 
  

  

  These 
  concretions 
  are 
  flattened, 
  and 
  were 
  found 
  piled 
  upon 
  

   each 
  other 
  horizontally, 
  the 
  larger 
  one 
  occupying 
  the 
  base 
  and 
  

   the 
  smaller 
  one 
  the 
  apex, 
  thus 
  forming 
  a 
  regular 
  tapering 
  up- 
  

   right 
  cone. 
  The 
  diameter 
  of 
  the 
  largest 
  concretion 
  is 
  one 
  foot, 
  

   and 
  of 
  the 
  smallest 
  six 
  inches 
  ; 
  and 
  the 
  aggregate 
  height 
  of 
  all 
  is 
  

   eleven 
  inches. 
  A 
  vertical 
  nucleus 
  appears 
  to 
  pass 
  through 
  the 
  

   centre 
  of 
  the 
  mass, 
  around 
  which 
  the 
  flattened 
  spheroids 
  were 
  • 
  

   formed. 
  The 
  law 
  of 
  segregation, 
  or 
  rather 
  molecular 
  attraction, 
  

   will 
  explain 
  and 
  account 
  for 
  the 
  formation 
  of 
  the 
  several 
  con- 
  

   cretions 
  ', 
  but 
  the 
  general 
  principle 
  or 
  law, 
  which 
  governed 
  the 
  

   whole 
  mass, 
  and 
  produced 
  symmetry 
  of 
  form 
  and 
  harmony 
  of 
  

   arrangement, 
  is 
  not 
  fully 
  understood, 
  and 
  is 
  worthy 
  of 
  conside- 
  

   ration. 
  

  

  The 
  appearance 
  of 
  the 
  spheroids 
  as 
  they 
  were 
  found 
  imbedded 
  

   in 
  the 
  shale, 
  will 
  be 
  more 
  fully 
  comprehended 
  from 
  the 
  follow- 
  

   ing 
  drawing 
  : 
  

  

  