﻿158 
  Scientific 
  Intelligence. 
  

  

  eral 
  formations 
  finds 
  its 
  northernmost 
  extension 
  in 
  the 
  Sand 
  Hills 
  

   north 
  of 
  Monmouth 
  Junction. 
  It 
  caps 
  various 
  high 
  hills 
  in 
  Mon- 
  

   mouth 
  County, 
  where 
  it 
  reaches 
  its 
  greatest 
  elevation. 
  South- 
  

   ward 
  the 
  formation 
  becomes 
  lower 
  and 
  at 
  the 
  same 
  time 
  much 
  

   more 
  continuous. 
  In 
  general 
  it 
  is 
  essentially 
  continuous 
  south 
  of 
  

   the 
  line 
  where 
  the 
  Middle 
  Marl 
  bed 
  comes 
  to 
  the 
  surface. 
  This 
  

   formation 
  has 
  essentially 
  the 
  same 
  dip 
  as 
  the 
  Cretaceous 
  beds 
  

   beneath. 
  That 
  it 
  is 
  not 
  strictly 
  conformable 
  with 
  the 
  Cretaceous 
  

   is 
  shown 
  by 
  the 
  fact 
  that 
  it 
  overlies 
  different 
  members 
  of 
  the 
  Cre- 
  

   taceous 
  series 
  in 
  different 
  areas. 
  The 
  relations 
  are 
  such 
  as 
  to 
  

   show 
  that 
  the 
  main 
  part 
  of 
  the 
  deformation 
  of 
  the 
  Cretaceous 
  beds 
  

   took 
  place 
  after 
  this 
  oldest 
  " 
  Yellow 
  Gravel 
  " 
  formation 
  was 
  laid 
  

   down. 
  Professor 
  W. 
  B. 
  Clark 
  has 
  reached 
  the 
  conclusion 
  that 
  

   this 
  formation 
  is 
  Miocene. 
  After 
  it 
  was 
  deposited, 
  there 
  was 
  a 
  

   period 
  of 
  uplift 
  accompanied 
  by 
  deformation. 
  This 
  was 
  followed 
  

   by 
  a 
  long 
  period 
  of 
  erosion, 
  during 
  which 
  a 
  large 
  part 
  of 
  the 
  for- 
  

   mation, 
  especially 
  to 
  the 
  north, 
  was 
  destroyed 
  by 
  subaerial 
  

   agencies. 
  During 
  this 
  time 
  of 
  erosion 
  central 
  Jersey 
  was 
  reduced 
  

   to 
  a 
  peneplain. 
  Subsequently 
  the 
  central 
  and 
  southern 
  parts 
  of 
  

   Jersey 
  were 
  again 
  submerged, 
  and 
  there 
  was 
  deposited 
  on 
  the 
  

   peneplain, 
  the 
  second 
  member 
  (the 
  Pensauken 
  formation) 
  of 
  the 
  

   " 
  Yellow 
  Gravel 
  " 
  series. 
  Above 
  the 
  Pensauken 
  sea 
  stood 
  a 
  con- 
  

   siderable 
  number 
  of 
  hills 
  capped 
  by 
  Miocene. 
  The 
  Pensauken 
  is 
  

   best 
  developed 
  along 
  the 
  trough-like 
  depression 
  which 
  extends 
  

   from 
  the 
  vicinity 
  of 
  Trenton 
  northeastward 
  to 
  Raritan 
  bay. 
  The 
  

   Pensauken 
  formation 
  is 
  made 
  up 
  of 
  constituents 
  which 
  came 
  from 
  

   very 
  diverse 
  sources. 
  The 
  Triassic 
  shale, 
  and 
  most, 
  if 
  not 
  all 
  the 
  

   formations 
  of 
  the 
  highlands 
  of 
  northern 
  New 
  Jersey 
  made 
  their 
  

   contributions, 
  as 
  well 
  as 
  the 
  Cretaceous 
  and 
  Miocene. 
  All 
  decom- 
  

   posable 
  constituents 
  of 
  the 
  formation 
  are 
  completely 
  decayed. 
  

   This 
  formation 
  originally 
  reached 
  at 
  least 
  as 
  far 
  north 
  as 
  the 
  

   Watchung 
  Mountains. 
  During 
  the 
  uplift 
  which 
  followed 
  the 
  

   deposition, 
  there 
  was 
  slight 
  deformation, 
  the 
  elevation 
  being 
  

   greatest 
  in 
  the 
  region 
  which 
  suffered 
  greatest 
  uplift 
  after 
  the 
  

   deposition 
  of 
  the 
  Miocene 
  beds. 
  Erosion 
  followed, 
  and 
  a 
  well 
  

   developed 
  system 
  of 
  drainage 
  was 
  established 
  on 
  the 
  Pensauken 
  

   surface. 
  Subsequently 
  subsidence 
  and 
  a 
  considerable 
  degree 
  of 
  

   submergence 
  followed, 
  so 
  that 
  much 
  of 
  the 
  Pensauken 
  formation 
  

   (its 
  lower 
  parts) 
  and 
  the 
  valleys 
  which 
  were 
  cut 
  in 
  it, 
  received 
  a 
  

   new 
  mantle 
  of 
  loam 
  and 
  gravel. 
  This 
  is 
  known 
  as 
  the 
  Jamesburg 
  

   formation. 
  Subsequent 
  to 
  the 
  deposition 
  of 
  the 
  Jamesburg, 
  the 
  

   Trenton 
  gravels 
  were 
  deposited 
  in 
  the 
  Delaware 
  valley, 
  during 
  

   the 
  last 
  glacial 
  epoch 
  which 
  affected 
  New 
  Jersey. 
  About 
  the 
  

   eastern 
  and 
  southern 
  coasts 
  of 
  the 
  state 
  there 
  is 
  a 
  broad, 
  ill 
  defined 
  

   terrace, 
  having 
  a 
  general 
  altitude 
  of 
  about 
  forty-five 
  feet, 
  which 
  

   may 
  or 
  may 
  not 
  correspond 
  in 
  age 
  with 
  the 
  Trenton 
  gravels. 
  

   This 
  broad 
  terrace 
  is 
  certainly 
  much 
  younger 
  than 
  the 
  body 
  of 
  

   the 
  Jamesburg 
  formation, 
  though 
  it 
  may 
  represent 
  no 
  more 
  than 
  

   a 
  halt 
  in 
  the 
  emergence 
  which 
  followed 
  the 
  deposition 
  of 
  the 
  body 
  

   of 
  that 
  formation. 
  The 
  correlation 
  of 
  these 
  various 
  subdivisions 
  

  

  