﻿HUDSON 
  RIVER 
  BEDS 
  NEAR 
  ALBANY 
  577 
  

  

  T 
  u 
  r 
  r 
  i 
  1 
  e 
  p 
  a 
  s 
  (?) 
  f 
  i 
  1 
  o 
  s 
  u 
  s 
  , 
  sp. 
  n. 
  (sec 
  pi. 
  2, 
  fig. 
  13, 
  14, 
  15). 
  

  

  In 
  the 
  lower 
  Utica 
  shale 
  of 
  Mechanicsville, 
  two 
  plates 
  were 
  

   found, 
  which 
  in 
  size, 
  outline 
  and 
  surface 
  ornamentation 
  greatly 
  

   differ 
  from 
  the 
  minute 
  plates 
  of 
  Lepidocoleus 
  jamesi, 
  

   associated 
  with 
  them 
  in 
  great 
  number. 
  Both 
  plates, 
  though 
  of 
  

   different 
  size, 
  are 
  so 
  clearly 
  alike 
  in 
  outline 
  and 
  sculpture 
  that 
  

   they 
  undoubtedly 
  belong 
  to 
  the 
  same 
  species. 
  

  

  Plates 
  obliquely 
  subtriangular, 
  comparable 
  in 
  outline 
  to 
  an 
  

   isosceles 
  triangle 
  with 
  the 
  apex 
  pushed 
  to 
  one 
  side; 
  the 
  nucleus 
  

   falling 
  into 
  the 
  apex, 
  and 
  the 
  two 
  legs 
  standing 
  nearly 
  vertical 
  

   on 
  the 
  slightly 
  convex 
  base; 
  the 
  lengthened 
  side 
  strongly 
  convex, 
  

   the 
  shortened 
  nearly 
  straight; 
  surface 
  marked 
  by 
  strongly 
  ele- 
  

   vated, 
  very 
  regular 
  concentric 
  lines, 
  which 
  have 
  multiplied 
  more 
  

   rapidly 
  on 
  the 
  posterior 
  side. 
  

  

  Dimensions. 
  The 
  smaller 
  specimen 
  measures 
  4 
  mm 
  along 
  the 
  

   base, 
  and 
  4.5 
  mm 
  along 
  the 
  vertical 
  side; 
  the 
  larger 
  7 
  mm 
  and 
  9 
  

   mm 
  in 
  the 
  same 
  directions. 
  

  

  Both 
  valves 
  figured 
  differ 
  markedly 
  from 
  the 
  typical 
  plates 
  of 
  

   Turrilepas 
  by 
  their 
  outline, 
  the 
  absence 
  of 
  the 
  sigmoidal 
  

   curvature 
  in 
  the 
  base, 
  their 
  relatively 
  larger 
  size, 
  and 
  the 
  char- 
  

   acter 
  of 
  the 
  concentric 
  striae, 
  which 
  appear 
  not 
  as 
  the 
  edges 
  of 
  im- 
  

   bricating 
  layers, 
  but 
  as 
  strongly 
  elevated 
  lines 
  with 
  deep,, 
  even 
  in- 
  

   terspaces 
  and 
  by 
  the 
  conical 
  shape 
  which 
  they 
  probably 
  possessed 
  

   originally; 
  for 
  they 
  present 
  the 
  appearance 
  of 
  convex 
  bodies 
  

   which 
  became 
  flattened 
  in 
  fossilization. 
  This 
  is 
  specially 
  dis- 
  

   tinct 
  in 
  the 
  smaller 
  specimen 
  (pi. 
  2, 
  fig. 
  13), 
  where 
  a 
  median 
  

   furrow 
  or 
  break 
  separates 
  two 
  differently 
  convex 
  halves. 
  In 
  all 
  

   these 
  features 
  they 
  agree 
  with 
  another 
  group 
  of 
  valves 
  which 
  

   have 
  been 
  doubtfully 
  referred 
  to 
  Turrilepas 
  by 
  Whitfield 
  

   (Armals 
  New 
  York 
  acad. 
  sci. 
  1882, 
  v. 
  2. 
  no. 
  8. 
  p. 
  217) 
  and 
  by 
  

   Hall 
  and 
  Clarke 
  (Pat. 
  N. 
  Y. 
  1888. 
  7:219). 
  The 
  latter 
  authors 
  

   remark 
  "that 
  it 
  is 
  difficult 
  to 
  see 
  how 
  the 
  combination 
  of 
  

   these 
  subcorneal 
  bodies 
  in 
  vertical 
  ranges 
  could 
  produce 
  such 
  

   a 
  scaly 
  peduncle 
  or 
  capitulum 
  as 
  existed 
  in 
  Turrilepas" 
  

   and 
  point 
  out 
  their 
  resemblance 
  with 
  Spathiocaris. 
  This 
  

   form 
  (Turrilepas 
  (?) 
  newberryi), 
  from 
  which 
  ours 
  dif- 
  

  

  