HIGHLANDS    o|'    XKW    JERSEY.  635 
formable  with  the  basal  gneisses  in  the  New  York  City  quadrangle, 
the  difference  in  the  apparent  relations  in  the  two  areas  may  be  ex- 
plained by  partial  overlap. 
SECTION  3.     HIGHLANDS   OF  NEW  JERSEY. 
SUMMARY  OF  LITERATURE. 
Va.ntuxem  and  Keating,03  in  L821,  state  thai  the  country  around 
Franklin  is  composed  of  syenite,  which  is  found  in  beds  or  layers  of 
variable  thickness,  running  in  a  direction  parallel  to  that  of  the 
ridge.  A  white  limestone  forms  a  bed  with  eminently  crystalline 
structure,  the  inclination,  direction,  and  dip  of  which  are  the  same 
as  those  of  the  syenite.  This  limestone  has  been  traced  for  a  dis- 
tance of  8  miles,  and,  although  the  lime-tone  is  subordinate  to  the 
syenite,  masses  of  the  latter  are  found  in  it.  At  Franklin,  next  to 
the  syenite,  are  found  masses  of  graywacke,  which,  on  the  road  from 
Franklin  to  Doctor  Fowler's,  is  seen  to  he  superimposed  upon  the 
syenite  and  is  evidently  a  later  formation.  About  a  quarter  of  a 
mile  below  the  furnace  it  is  covered  with  a  violet  limestone,  which 
rests  upon  it  in  parallel  superposition.  This  limestone  and  that 
associated  with  the  syenite  are  not  of  contemporaneous  origin,  hut 
the  blue  limestone  is  a  real  mantle-formed  superposition. 
Pierce,94  in  1822,  describes  the  Highland  range-  as  Primitive,  with 
the  exception  of  an  isolated  Transition  region.  The  rocks  here  in- 
cluded are  granite,  gneiss,  and  syenite,  while  in  the  Transition  are 
found  graywacke,  graywacke  slate,  chlorite  slate,  and  lime-lone. 
Rogers  (II.  D.),95  in  1840,  gives  a  systematic  account  of  the  Pri- 
mary rocks  of  New  Jersey.  'These  are  almost  exclusively  of  the 
stratified  class,  consisting  of  gneiss  under  all  its  forms,  the  granitoid 
variety  predominating.  Innumerable  small  veins  of  feldspathic 
granite,  syenite,  greenstone,  etc..  penetrate  the  gneiss.  The  gneiss  is 
comparatively  seldom  of  the  schistose  kind.  Mica  is  deficient,  the 
usual  mixture  being  either  feldspar  or  quartz  with  a  little  mica,  or 
these  minerals  with  an  excess  of  hornblende,  and  hornblende  and 
magnetic  oxide  of  iron,  the  latter  being  so  abundant  a-  t<>  be  a  char- 
acteristic constituent.  It  occurs  not  only  as  an  occasional  ingredient 
of  the  gneiss,  but  in  great  dikes  or  veins  penetrating  the  strata.  The 
massive  granitoid  gneisses  of  the  Highlands  are  in  striking  contrast 
with  the  gneiss  belt  of  New  York  and  Staten  [sland,  which  reappears 
at  Trenton  and  ranges  through  Pennsylvania  and  Maryland,  which 
IS  distinguished  by  the  prevalence  of  mica  and  other  thinly  laminated 
minerals,  imparting  to  the  rock  a  schistose  structure  or  the  thinly 
bedded  character  of  ordinary  gneiss.  The  massive  strata  are,  on  the 
whole,  decidedly  less  extensive  than   in  the  Philadelphia  belt.     They 
