﻿REPORT 
  OF 
  THE 
  DIRECTOR 
  r45 
  

  

  Conclusions 
  

  

  The 
  stvidy 
  of 
  so 
  limited 
  an 
  area 
  as 
  Frankfort 
  Hill 
  affords 
  insuffi- 
  

   cient 
  data 
  from 
  which 
  to 
  draw 
  conclusions 
  of 
  any 
  very 
  general 
  

   character. 
  The 
  sections 
  examined, 
  however, 
  show 
  the 
  following 
  

   noteworthy 
  facts 
  : 
  

  

  First, 
  That 
  the 
  Frankfort 
  slates 
  have 
  a 
  very 
  considerable 
  thick- 
  

   ness, 
  and 
  are 
  almost 
  entirely 
  barren 
  of 
  fossil 
  remains. 
  Yanuxem 
  

   ('40 
  p. 
  373) 
  has 
  suggested 
  the 
  presence 
  of 
  saline 
  matter, 
  unfavorable 
  

   to 
  the 
  existence 
  or 
  development 
  of 
  life, 
  in 
  order 
  to 
  explain 
  the 
  fact 
  

   '*tbat 
  organic 
  life 
  abounded 
  in 
  the 
  period 
  of 
  the 
  Trenton 
  limestone, 
  

   and 
  disappeared 
  in 
  the 
  lower 
  part 
  of 
  the 
  Black 
  (Utica) 
  slate, 
  reap- 
  

   pearing 
  only 
  in 
  the 
  upper 
  part 
  of 
  the 
  Frankfort 
  slate, 
  leaving 
  a 
  

   thickness 
  of 
  mud 
  rock 
  of 
  at 
  least 
  400 
  feet, 
  comparatively 
  destitute 
  

   of 
  organic 
  bodies." 
  

  

  Second. 
  That 
  the 
  upper 
  beds 
  of 
  the 
  Frankfort 
  gulf 
  section 
  grade 
  

   into 
  barren 
  fine-grained 
  sandstones 
  (indicating 
  approaching 
  shore- 
  

   conditions), 
  which 
  very 
  closely 
  resemble 
  the 
  Medina^ 
  even 
  if 
  the 
  

   latter 
  in 
  this 
  locality 
  be 
  represented 
  chiefly 
  by 
  the 
  coarse 
  conglom- 
  

   erates 
  of 
  beach 
  deposits 
  of 
  the 
  Oneida, 
  with 
  its 
  coarser 
  interbedded 
  

   sandstones 
  and 
  occasional 
  intercalated 
  dark 
  layers 
  of 
  shale. 
  

  

  V^ery 
  abrupt 
  shoaling 
  to 
  the 
  Oneida 
  phase 
  took 
  place 
  with 
  strong 
  

   currents 
  and 
  the 
  conditions 
  of 
  the 
  wash 
  of 
  a 
  beach. 
  (Hall 
  '83 
  p. 
  45.) 
  

  

  Third. 
  There 
  followed 
  a 
  series 
  of 
  alternations 
  between 
  beach 
  and 
  

   mud-flat 
  conditions, 
  not 
  at 
  all 
  unlike 
  those 
  in 
  progress 
  along 
  the 
  

   inlets 
  of 
  the 
  New 
  Jersey 
  shore 
  to-day. 
  The 
  result 
  was 
  the 
  complex 
  

   series 
  of 
  Clinton 
  beds 
  to 
  which 
  Yanuxem 
  ('38 
  p. 
  284) 
  gave 
  the 
  

   name 
  " 
  Protean 
  group," 
  stating 
  its 
  thickness 
  as 
  200 
  feet. 
  Our 
  

   measurements 
  make 
  the 
  thickness 
  a 
  little 
  greater 
  than 
  this. 
  

   The 
  Clinton 
  fossils 
  of 
  nearly 
  all 
  the 
  layers, 
  especially 
  of 
  sections 
  

   D 
  and 
  E 
  of 
  the 
  Chad 
  wick 
  Mills 
  section, 
  have 
  a 
  slimy 
  coating 
  upon 
  

   their 
  surfaces, 
  which 
  it 
  is 
  almost 
  impossible 
  to 
  remove. 
  The 
  sur- 
  

   faces 
  of 
  the 
  slate 
  and 
  the 
  irregular 
  partings 
  likewise 
  partake 
  

   of 
  this 
  slimy 
  appearance. 
  There 
  is 
  evidence 
  of 
  quick 
  deposi- 
  

   tion, 
  similar 
  to 
  that 
  of 
  the 
  Jurassic, 
  while 
  the 
  existing 
  land 
  was 
  

   evidently 
  in 
  the 
  nature 
  of 
  mud 
  and 
  sand 
  flats, 
  w^ashed 
  by 
  sluggish 
  

  

  a 
  On 
  changes 
  of 
  level 
  affecting 
  sedimentation 
  and 
  on 
  cycles 
  of 
  deposition 
  see 
  Dawson 
  '66 
  

   p. 
  102 
  and 
  '78 
  p. 
  135-138; 
  Giekie 
  '82 
  p. 
  484: 
  Hunt 
  '63 
  and 
  '74; 
  Newberry 
  '73, 
  '74, 
  '74a 
  and 
  '75; 
  

   Dawson 
  '63 
  p. 
  96. 
  

  

  