﻿Hansome 
  — 
  I^ew 
  Occurrence 
  of 
  Nepheline 
  Syenite. 
  419 
  

  

  f 
  erred 
  to 
  a 
  recent 
  paper 
  bj 
  Kiimmel.^ 
  A 
  word 
  or 
  two, 
  how- 
  

   ever, 
  may 
  not 
  be 
  out 
  of 
  place 
  in 
  explanation 
  of 
  the 
  accompany- 
  

   ing 
  sketch-map 
  (fig. 
  1.), 
  which 
  is 
  taken 
  from 
  the 
  Lambert 
  ville 
  

   topographic 
  sheet 
  of 
  the 
  U. 
  S. 
  Geological 
  Sarvej. 
  For 
  the 
  

   general 
  geological 
  data 
  I 
  am 
  indebted 
  to 
  Mr. 
  Darton, 
  and 
  to 
  

   the 
  paper 
  by 
  Klimmel 
  already 
  mentioned. 
  

  

  The 
  Mt. 
  Gilboa 
  trap-mass 
  lies 
  between 
  two 
  faults 
  — 
  the 
  Flem- 
  

   ington 
  fault 
  on 
  the 
  northwest, 
  and 
  the 
  Dilts 
  Corner 
  fault 
  on 
  

   the 
  southeast, 
  both 
  of 
  which 
  are 
  only 
  partly 
  shown 
  on 
  the 
  sketch- 
  

   map. 
  In 
  each 
  case 
  the 
  rocks 
  lying 
  southeast 
  of 
  the 
  line 
  of 
  dis- 
  

   location 
  are 
  on 
  the 
  downthrow 
  side 
  of 
  the 
  fracture. 
  JS^orth- 
  

   west 
  of 
  the 
  Fleniington 
  fault, 
  in 
  Xew 
  Jersey, 
  lie 
  the 
  arkose 
  

   sandstones 
  and 
  conglomerates 
  of 
  the 
  Stockton 
  series 
  of 
  the 
  

   ]N"ewark, 
  the 
  beds 
  dipping 
  westerly. 
  On 
  the 
  Pennsylvania 
  side 
  

   of 
  the 
  river 
  however. 
  Palaeozoic 
  limestone 
  is 
  exposed 
  between 
  

   the 
  base 
  of 
  the 
  Stockton 
  beds 
  and 
  the 
  fault-line. 
  Southeast 
  of 
  

   the 
  Dilts 
  Corner 
  fault, 
  the 
  soft 
  red 
  shales 
  of 
  the 
  Brunswick 
  

   series 
  extend 
  down 
  the 
  river 
  to 
  the 
  trap 
  masses 
  below 
  Lambert- 
  

   ville. 
  Between 
  the 
  two 
  fault-lines 
  the 
  rocks 
  consist 
  of 
  the 
  dark 
  

   shales 
  of 
  the 
  Lockatong 
  series, 
  the 
  Mt. 
  Gilboa 
  trap-mass, 
  and 
  

   several 
  smaller 
  bodies 
  of 
  trap, 
  not 
  shown 
  on 
  the 
  sketch-map. 
  

   The 
  trap 
  is 
  regarded 
  by 
  Iviimmel 
  as 
  intrusive, 
  and 
  his 
  view 
  is 
  

   undoubtedly 
  correct, 
  for 
  the 
  shales 
  just 
  west 
  of 
  the 
  main 
  trap- 
  

   mass 
  are 
  metamorphosed 
  near 
  the 
  contact 
  into 
  quartz-biotite 
  

   hornfels 
  — 
  a 
  line-o^rained 
  crystalline 
  ao-^reo-ate 
  of 
  quartz, 
  biotite 
  

   and 
  probably 
  feldspar. 
  

  

  The 
  nepheline 
  syenite 
  was 
  found 
  on 
  the 
  northwest 
  edge 
  of 
  

   the 
  main 
  body 
  of 
  trap, 
  just 
  below 
  the 
  forks 
  of 
  a 
  little 
  brook 
  

   which 
  flows 
  into 
  the 
  Delaware 
  about 
  a 
  quarter 
  of 
  a 
  mile 
  south 
  

   of 
  Brookville. 
  The 
  exposure 
  is 
  not 
  more 
  than 
  a 
  few 
  square 
  

   yards 
  in 
  extent, 
  and 
  the 
  contact 
  with 
  the 
  ordinary 
  fine-grained 
  

   trap, 
  which 
  surrounds 
  the 
  nepheline 
  syenite 
  on 
  at 
  least 
  three 
  

   sides, 
  was 
  nowhere 
  seen. 
  Closely 
  associated 
  with 
  the 
  nephe- 
  

   line 
  syenite 
  and 
  with 
  the 
  trap 
  is 
  a 
  micaceous 
  syenite, 
  exposed 
  

   in 
  the 
  bed 
  of 
  the 
  brook 
  just 
  at 
  the 
  forks. 
  Like 
  the 
  nepheline 
  

   syenite, 
  this 
  rock 
  is 
  apparently 
  limited 
  in 
  its 
  occurrence 
  to 
  a 
  

   small 
  mass, 
  the 
  exact 
  relations 
  of 
  which 
  to 
  the 
  adjacent 
  rocks 
  

   were 
  not 
  discoverable 
  in 
  the 
  field. 
  

  

  Xear 
  the 
  southern 
  end 
  of 
  the 
  Mt. 
  Gilboa 
  trap-mass, 
  just 
  

   north 
  of 
  Barbour 
  ct 
  Ireland's 
  quarry, 
  a 
  small 
  mass 
  of 
  syenitic 
  

   rock 
  occurs 
  enclosed 
  in 
  the 
  trap, 
  but 
  here 
  also 
  the 
  exposures 
  

   are 
  inadequate 
  to 
  determine 
  the 
  exact 
  extent 
  of 
  the 
  mass 
  and 
  

   the 
  relation 
  which 
  it 
  bears 
  to 
  the 
  trap. 
  

  

  The 
  two 
  localities 
  referred 
  to 
  in 
  the 
  preceding 
  paragraphs 
  

  

  * 
  The 
  Xewark 
  System 
  or 
  Red 
  Sandstone 
  Belt 
  of 
  New 
  Jersey. 
  Annual 
  Rept. 
  of 
  

   the 
  State 
  Geologist, 
  1897, 
  pp. 
  32, 
  75, 
  109-110, 
  etc.; 
  also 
  pi. 
  ii. 
  and 
  fig. 
  9. 
  

  

  