﻿THE 
  TERTIARY 
  FORMATIONS 
  OF 
  VIRGINIA. 
  339 
  

  

  at 
  this 
  point 
  appears 
  to 
  be 
  about 
  twenty 
  feet. 
  At 
  distant 
  points, 
  where 
  

   this 
  deposit 
  has 
  been 
  examined, 
  as 
  for 
  instance 
  near 
  the 
  Piping 
  Tree, 
  

   on 
  Pamunkey, 
  and 
  near 
  Port 
  Royal, 
  on 
  the 
  Rappahannock, 
  as 
  well 
  as 
  upon 
  

   the 
  Potomac, 
  much 
  the 
  same 
  arrangement 
  and 
  succession 
  of 
  strata 
  have 
  

   been 
  remarked. 
  

  

  39. 
  The 
  section 
  at 
  Coggins 
  Point 
  presents 
  the 
  interesting 
  feature 
  

   of 
  a 
  juxtaposition 
  in 
  the 
  same 
  cliff, 
  of 
  the 
  Eocene 
  and 
  newer 
  Tertiary 
  

   formations, 
  and 
  on 
  this 
  account 
  must 
  be 
  regarded 
  as 
  an 
  important 
  

   locality. 
  

  

  The 
  fact 
  too 
  that 
  in 
  this 
  as 
  well 
  as 
  other 
  places 
  where 
  the 
  Eocene 
  

   deposit 
  has 
  been 
  discovered, 
  so 
  very 
  large 
  a 
  proportion 
  of 
  the 
  chloritic 
  

   sand 
  is 
  contained 
  in 
  the 
  matter 
  embedding 
  the 
  fossils, 
  is, 
  we 
  presume, 
  

   an 
  unexpected 
  and 
  interesting 
  circumstance. 
  Even 
  the 
  New 
  Jersey 
  

   secondary 
  strata 
  are 
  seldom 
  more 
  abundant 
  in 
  this 
  peculiar 
  mineral 
  

   product 
  than 
  the 
  formation 
  referred 
  to, 
  and 
  hence 
  the 
  farmers 
  of 
  Vir- 
  

   ginia 
  are, 
  beginning 
  to 
  apply 
  this 
  material 
  to 
  their 
  fields. 
  

  

  VI. 
  NEW 
  FOSSIL. 
  SHELLS 
  OF 
  THE 
  Eo'cENE 
  OF 
  VIRGINIA. 
  

  

  . 
  , 
  - 
  Nucula 
  cultelliformis. 
  

  

  40. 
  Shell 
  ovate, 
  ensiform, 
  somewhat 
  inflated, 
  rounded 
  before, 
  

   much 
  elongated, 
  and 
  tapering 
  behind, 
  the 
  posterior 
  length 
  more 
  than 
  

   twice 
  the 
  anterior, 
  furnished 
  with 
  very 
  fine, 
  hardly 
  distinct 
  concentric 
  

   striae, 
  and 
  one 
  distinct 
  and 
  one 
  very 
  obscure 
  rib 
  behind 
  ; 
  anterior 
  part 
  

   with 
  an 
  indistinct 
  fold 
  ; 
  shell 
  thin 
  ; 
  lunule 
  long 
  and 
  lanceolate 
  ; 
  beak 
  

   small 
  ; 
  anterior 
  series 
  of 
  the 
  teeth 
  gently 
  arched 
  ; 
  posterior 
  series 
  straight 
  ; 
  

   teeth 
  in 
  both 
  acutely 
  bent, 
  the 
  angles 
  directed 
  towards 
  the 
  beak; 
  mar- 
  

   gin 
  entire 
  ; 
  cavity 
  of 
  shell 
  shallow, 
  with 
  a 
  ridge 
  passing 
  from 
  the 
  beak 
  

   to 
  the 
  posterior 
  margin. 
  Transverse 
  length, 
  twenty-eight 
  hundredths 
  ; 
  

   height, 
  eight 
  hundredths 
  of 
  an 
  inch. 
  

  

  Locality, 
  Coggins 
  Point, 
  Prince 
  George 
  county, 
  in 
  the 
  green 
  sand 
  

   stratum. 
  This 
  very 
  delicate 
  shell 
  approaches 
  nearest 
  to 
  the 
  N. 
  media 
  

   of 
  Lea, 
  the 
  iEqualis 
  of 
  Conrad, 
  but 
  differs 
  in 
  the 
  great 
  elongation 
  of 
  

  

  and 
  a 
  half 
  feet 
  ; 
  and 
  its 
  weight 
  is 
  probably 
  seven 
  or 
  eight 
  hundred 
  pounds. 
  On 
  the 
  shore 
  are 
  

   likewise 
  found 
  vast 
  numbers 
  of 
  the 
  teeth 
  of 
  sharks, 
  some 
  of 
  them 
  of 
  enormous 
  dimensions. 
  

  

  