﻿Ransome 
  — 
  Neio 
  Occurrence 
  of 
  Nepheline 
  Syenite. 
  417 
  

  

  Art. 
  XLYIII. 
  — 
  On 
  a 
  New 
  Occurrence 
  of 
  Nepheline 
  Syenite 
  in 
  

   JSew 
  Jersey 
  ■; 
  ^ 
  by 
  F. 
  Leslie 
  Eansome. 
  

  

  Introduction: 
  

  

  Through 
  the 
  kindness 
  of 
  Mr. 
  I^. 
  H. 
  Darton, 
  there 
  recently 
  

   came 
  into 
  my 
  hands 
  a 
  few 
  rock-specimens 
  which 
  he 
  had 
  col- 
  

   lected 
  near 
  Brookville, 
  N. 
  J., 
  in 
  the 
  course 
  of 
  general 
  areal 
  work 
  

   on 
  the 
  Trenton 
  folio 
  of 
  the 
  Geological 
  Atlas 
  of 
  the 
  U. 
  S. 
  The 
  

   specimens 
  were 
  stated 
  by 
  him 
  to 
  have 
  come 
  from 
  a 
  mass 
  of 
  trap 
  

   intrusive 
  into 
  the 
  Newark 
  formation, 
  and 
  were 
  supposed, 
  when 
  

   collected, 
  to 
  be 
  variations 
  from 
  the 
  usual 
  and 
  normal 
  facies 
  of 
  

   the 
  common 
  trap-rock 
  of 
  the 
  region. 
  Upon 
  examination, 
  one 
  

   of 
  the 
  specimens 
  proved 
  to 
  be 
  a 
  nepheline 
  syenite, 
  and 
  two 
  of 
  

   the 
  others 
  hornblende 
  and 
  biotite 
  syenites 
  respectively. 
  The 
  

   original 
  specimens 
  furnished 
  by 
  Mr. 
  Darton 
  were 
  studied 
  petro- 
  

   graphically, 
  and 
  a 
  chemical 
  analysis 
  of 
  the 
  nepheline 
  syenite 
  

   was 
  made 
  by 
  Mr. 
  George 
  Steiger 
  of 
  the 
  Geological 
  Survey. 
  

   Subsequently 
  a 
  brief 
  visit 
  was 
  paid 
  to 
  the 
  locality, 
  additional 
  

   material 
  secured, 
  and 
  some 
  attempt 
  made 
  to 
  ascertain 
  the 
  rela- 
  

   tion 
  of 
  the 
  syenitic 
  rocks 
  to 
  the 
  ordinary 
  trap 
  with 
  which 
  they 
  

   are 
  closely 
  associated. 
  This 
  last 
  was 
  but 
  partly 
  successful, 
  as 
  

   will 
  appear 
  from 
  the 
  following 
  preliminary 
  notes. 
  

  

  Occurrence 
  of 
  the 
  Nepheline 
  Syenite 
  and 
  Associated 
  Hocks. 
  

   Brookville 
  is 
  a 
  small 
  village 
  on 
  the 
  Delaware, 
  in 
  the 
  south- 
  

   western 
  part 
  of 
  Hunterdon 
  County, 
  and 
  is 
  readily 
  reached 
  from 
  

   Trenton 
  by 
  the 
  Belvidere 
  Division 
  of 
  the 
  Pennsylvania 
  Kail- 
  

   road. 
  The 
  nearest 
  towns 
  of 
  importance 
  are 
  Lambertville, 
  about 
  

   2^ 
  miles 
  down 
  the 
  river, 
  and 
  Stockton, 
  about 
  a 
  mile 
  upstream. 
  

   As 
  shown 
  by 
  the 
  State 
  geological 
  map 
  of 
  l^ew 
  Jersey, 
  the 
  

   village 
  lies 
  almost 
  in 
  the 
  middle 
  of 
  the 
  broad 
  belt 
  of 
  the 
  so- 
  

   called 
  Triassic, 
  or 
  J^ewark 
  formation, 
  which 
  occupies 
  so 
  promi- 
  

   nent 
  a 
  place 
  in 
  the 
  geology 
  of 
  the 
  State. 
  On 
  the 
  same 
  map 
  

   there 
  is 
  indicated 
  the 
  relativel}^ 
  small 
  trap-mass 
  of 
  Mt. 
  Gilboa, 
  

   just 
  east 
  of 
  Brookville, 
  in 
  connection 
  with 
  which 
  occur 
  the 
  

   rocks 
  which 
  are 
  presently 
  to 
  be 
  described. 
  It 
  is 
  thus 
  seen 
  that 
  

   the 
  nepheline 
  syenite 
  of 
  Brookville 
  occurs 
  nearly 
  60 
  miles 
  a 
  

   little 
  west 
  of 
  south 
  from 
  the 
  well-known 
  Beemerville 
  locality, 
  

   and 
  in 
  rocks 
  of 
  entirely 
  different 
  age 
  and 
  character. 
  The 
  

   Beemerville 
  intrusions 
  are 
  in 
  the 
  Palaeozoic 
  rocks 
  of 
  what 
  Salis- 
  

   bury 
  f 
  has 
  called 
  the 
  Appalachian 
  Zone, 
  while 
  the 
  Brookville 
  

   masses 
  are 
  in 
  the 
  Mesozoic 
  rocks 
  of 
  the 
  Piedmont 
  Zone. 
  Be- 
  

   tween 
  these 
  two 
  physiographical 
  and 
  geological 
  provinces 
  lies 
  

   the 
  ancient 
  crystalline 
  zone 
  of 
  the 
  Highlands. 
  

  

  * 
  Published 
  with 
  the 
  permission 
  of 
  the 
  Director 
  of 
  the 
  U. 
  S. 
  Geological 
  Survey, 
  

   f 
  Physical 
  Geography 
  of 
  New 
  Jersey, 
  Geol. 
  Sutv. 
  of 
  N. 
  J., 
  vol. 
  v, 
  1895, 
  pp. 
  5-6, 
  

  

  Am. 
  Jour. 
  Sci. 
  — 
  Fourth 
  Series, 
  Yol. 
  YIII, 
  No. 
  48. 
  — 
  December, 
  1899. 
  

   29 
  

  

  