﻿Geology 
  and 
  Mineralogy. 
  159 
  

  

  with 
  formations 
  which 
  have 
  been 
  heretofore 
  recognized 
  is 
  not 
  now 
  

   attempted. 
  There 
  is 
  some 
  reason 
  to 
  believe 
  that 
  the 
  Pensauken 
  

   is 
  considerably 
  older 
  than 
  the 
  oldest 
  glacial 
  drift. 
  The 
  two 
  for- 
  

   mations 
  come 
  together 
  in 
  but 
  one 
  area, 
  and 
  there 
  the 
  relations 
  are 
  

   not 
  unequivocal. 
  The 
  general 
  constitution 
  of 
  the 
  Pensauken 
  for- 
  

   mation 
  would 
  ally 
  it 
  quite 
  as 
  closely 
  with 
  the 
  Lafayette 
  as 
  with 
  

   the 
  Columbia 
  of 
  the 
  regions 
  farther 
  south, 
  but 
  this 
  is 
  not 
  regar- 
  

   ded 
  as 
  a 
  sufficient 
  basis 
  for 
  so 
  correlating 
  it. 
  It 
  may 
  be 
  Pleisto- 
  

   cene, 
  antedating 
  the 
  earliest 
  drift 
  by 
  a 
  short 
  interval 
  only. 
  The 
  

   Jamesburg 
  formation 
  contains 
  occasional 
  glaciated 
  bowlders. 
  It 
  

   is 
  believed 
  to 
  be 
  later 
  in 
  origin 
  than 
  the 
  earliest 
  glacial 
  drift, 
  and 
  

   to 
  be 
  earlier 
  than 
  the 
  latest 
  glacial 
  drift. 
  Little 
  erosion 
  has 
  taken 
  

   place 
  since 
  it 
  was 
  laid 
  down. 
  Whether 
  this 
  is 
  the 
  result 
  of 
  a 
  

   shortness 
  of 
  time, 
  or 
  of 
  insufficient 
  elevation, 
  is 
  not 
  yet 
  certain. 
  

  

  C. 
  D. 
  Walcott, 
  in 
  a 
  paper 
  on 
  The 
  Appalachian 
  type 
  of 
  folding 
  

   in 
  the 
  White 
  Mountain 
  Range, 
  of 
  Inyo 
  County, 
  California, 
  gave 
  

   an 
  account 
  of 
  the 
  discovery 
  of 
  the 
  overturned 
  synclinal-anticlinal 
  

   structure 
  in 
  the 
  White 
  Mountain 
  range, 
  situated 
  east 
  of 
  the 
  

   Sierras, 
  similar 
  to 
  that 
  existing 
  in 
  the 
  Appalachian 
  Mountains 
  

   in 
  occupying 
  a 
  similar 
  position 
  to 
  those 
  on 
  the 
  opposite 
  side 
  of 
  the 
  

   continent. 
  In 
  a 
  second 
  paper 
  [Lower 
  Cambrian 
  Rocks 
  in 
  Eastern 
  

   California), 
  he 
  gave 
  an 
  account 
  of 
  the 
  discovery 
  of 
  Lower 
  Cam- 
  

   brian 
  rocks 
  and 
  fauna 
  in 
  the 
  same 
  range. 
  These 
  two 
  papers 
  will 
  

   appear 
  in 
  full 
  elsewhere 
  in 
  this 
  Journal. 
  Aethue 
  Keith 
  gave 
  an 
  

   interesting 
  analysis 
  of 
  the 
  structure 
  of 
  the 
  Southern 
  Appalachians 
  

   in 
  a 
  paper 
  on 
  New 
  structural 
  features 
  in 
  the 
  Appalachians. 
  His 
  

   paper 
  reviewed 
  the 
  generalizations 
  of 
  long 
  standing 
  in 
  regard 
  to 
  

   Appalachian 
  structure, 
  stated 
  and 
  analyzed 
  the 
  late 
  generaliza- 
  

   tions, 
  such 
  as 
  effect 
  of 
  bedding 
  planes, 
  of 
  superincumbent 
  lead, 
  of 
  

   initial 
  basins 
  of 
  deposit, 
  and 
  of 
  transmission 
  of 
  thrust, 
  upon 
  struc- 
  

   ture. 
  Finally, 
  statement 
  was 
  made 
  of 
  newly 
  discovered 
  structures, 
  

   such 
  as 
  fan 
  structure, 
  cross 
  folds, 
  cross 
  shear 
  zones, 
  secondary 
  

   system 
  of 
  folding 
  and 
  the 
  distribution 
  of 
  metamorphism 
  ; 
  and 
  a 
  

   theory 
  was 
  advanced 
  to 
  account 
  for 
  these 
  features 
  that 
  the 
  crys- 
  

   talline 
  rocks 
  moved 
  against 
  the 
  sediments, 
  chiefly 
  along 
  the 
  shear- 
  

   zones, 
  and 
  deformed 
  them 
  most 
  in 
  the 
  southwestern 
  Appalachians. 
  

  

  F. 
  B. 
  Adams 
  presented 
  an 
  excellent 
  paper 
  entitled 
  A 
  further 
  

   contribution 
  to 
  our 
  knowledge 
  of 
  the 
  Laurentian, 
  which 
  was 
  fully 
  

   illustrated 
  by 
  lantern 
  views 
  with 
  the 
  novelty 
  of 
  projecting 
  the 
  

   enlarged 
  rock 
  sections 
  directly 
  upon 
  the 
  screen. 
  Prof. 
  Adams 
  

   showed 
  that 
  essentially 
  two 
  types 
  of 
  rock 
  structure 
  are 
  to 
  be 
  

   found 
  in 
  the 
  metamorphosed 
  Laurentian 
  rocks, 
  one 
  a 
  purely 
  

   clastic 
  one, 
  the 
  other 
  one 
  in 
  which 
  recrystallization 
  has 
  taken 
  

   place 
  and 
  the 
  importance 
  of 
  these 
  in 
  discriminating 
  the 
  origin 
  of 
  

   these 
  rocks 
  was 
  pointed 
  out. 
  

  

  G. 
  K. 
  Gilbeet, 
  in 
  a 
  paper 
  on 
  the 
  formation 
  of 
  lake 
  basins 
  by 
  

   wind, 
  The 
  Tepee 
  Buttes, 
  by 
  G. 
  K. 
  Gilbert 
  and 
  F. 
  P. 
  Gullivee, 
  

   described 
  peculiar 
  geological 
  formations 
  examined 
  by 
  him 
  in 
  Colo- 
  

   rado. 
  Shallow 
  lakelets 
  reaching 
  \ 
  a 
  mile 
  in 
  greatest 
  diameter, 
  

   were 
  observed 
  in 
  the 
  arid 
  regions 
  in 
  eastern 
  Colorado 
  along 
  the 
  

  

  