﻿STRATIGRAPHIC 
  GEOLOGY 
  OF 
  THE 
  EASTERN 
  HELDERBERGS 
  349 
  

  

  Feet 
  

  

  A* 
  A 
  massive 
  dark 
  gray 
  limestone 
  which 
  breaks 
  into 
  36=114 
  

   very 
  irregular 
  blocks. 
  Fossils 
  are 
  not 
  very 
  plenti- 
  

   ful 
  and 
  are 
  very 
  difficult 
  to 
  obtain 
  unless 
  the 
  rock 
  

   has 
  been 
  slightly 
  burned. 
  This 
  formation 
  is 
  not 
  

   as 
  conspicuous 
  here 
  as 
  it 
  is 
  farther 
  north 
  and 
  the 
  

   dividing 
  line 
  between 
  it 
  and 
  the 
  Shaly 
  above 
  is 
  not 
  

   well 
  shown. 
  Pentamerus 
  limestone. 
  

  

  A 
  8 
  Limestone 
  which 
  in 
  appearance 
  and 
  fracture 
  is 
  12=78 
  

   much 
  like 
  the 
  Pentamerus 
  but 
  which 
  contains 
  a 
  

   mixture 
  of 
  the 
  Pentamerus 
  and 
  Tentaculite 
  faunas 
  

   and 
  is 
  transitional 
  between 
  these 
  two 
  formations. 
  

  

  A 
  a 
  Dark 
  blue 
  thin 
  bedded 
  limestone 
  which 
  breaks 
  into 
  40=66 
  

   almost 
  regular 
  blocks. 
  Tentaculite 
  limestone. 
  

  

  A 
  1 
  Covered 
  by 
  soil. 
  26=26 
  

  

  PALEONTOLOGY 
  

  

  The 
  following 
  species 
  were 
  collected 
  from 
  the 
  various 
  forma- 
  

   tions 
  about 
  Clarksville. 
  No 
  attempt 
  has 
  been 
  made 
  to 
  make 
  

   the 
  number 
  complete 
  for 
  any 
  formation. 
  

  

  A 
  2 
  Tentaculite 
  limestone: 
  

  

  1 
  Tentaculites 
  gyracanthus 
  (Eaton) 
  Hall 
  . 
  (aa) 
  

  

  2 
  Spirifer 
  vanuxemi 
  Hall 
  (a) 
  

  

  3 
  Stropheodonta 
  (Br 
  achy 
  priori) 
  vat 
  [striata 
  (Con.) 
  H. 
  (r) 
  

  

  4 
  Megambonia 
  aviculoidea 
  H. 
  (?) 
  (c) 
  

  

  5 
  Leperditia 
  alta 
  (Con.) 
  H. 
  (c) 
  

  

  6 
  Clw'etetes 
  (Monotrypella) 
  arbusculus 
  H. 
  (c) 
  

  

  A 
  3 
  Transitional 
  from 
  Tentaculite 
  to 
  Pentamerus 
  

  

  1 
  Leperditia 
  alta 
  (Con.) 
  Hall 
  (aa) 
  

  

  2 
  Spirifer 
  vanuxemi 
  H. 
  (r) 
  

  

  3 
  Avicula 
  communis 
  H. 
  (rr) 
  

  

  A 
  4 
  Pentamerus 
  limestone 
  

  

  1 
  Sieberella 
  galeata 
  (Dal.) 
  H. 
  & 
  G.-Pentamerus 
  galeatus 
  

  

  (Dal.) 
  (r) 
  

  

  2 
  Strophonella 
  punctulifera 
  (Con.) 
  H. 
  & 
  C. 
  (r) 
  

  

  3 
  Stropheodonta 
  (Br 
  achy 
  priori) 
  varistriata 
  (Con.) 
  H. 
  & 
  C. 
  (r) 
  

  

  