van  hise.]  EASTERN    UNITED    STATES.  355 
phosed  material.  The  gneisses  in  their  minerals,  inclusions,  and  mi- 
croscopic characters  are  like  granites,  and  pressure  may  have  been  as 
effective  m  producing  lateral  movements  and  forming  foliation  in  a 
plastic  mass  as  sedimentation.  If  the  stratification  of  the  gneiss  is 
then  regarded  as  an  induced  structure  it  would  not  follow  that  the 
stratification  should  correspond  with  the  original  bedding,  and  even  if 
the  lamination  does  correspond  with  the  plane  of  the  strata,  the  lami- 
nation can  not  be  referred  to  stratification  of  sediments,  for  the  cleavage 
of  the  adjacent  rocks  may  also  be  due  to  pressure  and  be  different  from 
the  plane  of  bedding.  The  greenstones,  including  metamorphic  diorite, 
quartz-diorite,  and  amphibolite,  are  regarded  as  metamorphosed  sedi- 
mentary rocks.  These  have  marked  lithological  distinctions  from  the 
fresh  basic  rocks  recognized  as  eruptives.  The  clay-slates  and  quartz- 
schists  are  semicrystalline  rocks.  The  slaty  cleavage  and  bedding 
are  sometimes  discordant. 
Hawes,15  in  1881,  describes  the  Albany  granite  as  penetrating  and 
metamorphosing  the  schists,  and  as  having  a  porphyritic  structure  near 
its  contact  with  them,  and  it  is  therefore  concluded  to  be  intrusive. 
Hitchcock,  (Ohas.  H.)16  in  1890,  regards  the  oval  granitoid  areas 
occurring  in  the  White  mountains,  about  which  occur  foliated  rocks 
with  an  anticlinal  quaquaversal  arrangement,  as  the  oldest  known  or 
fundamental  rocks  of  the  region  which  are  remains  of  an  ancient 
archipelago. 
Williams,16  in  1890,  with  the  same  facts  before  him  gives  an  exactly 
opposite  interpretation  to  Hitchcock,  that  is,  that  the  central  granites 
are  younger  intrusive  masses. 
LITERATURE    OF    VERMONT. 
Adams,17  in  1845,  divides  the  older  rocks  of  Vermont  into  Primary 
strata  and  Paleozoic  rocks.  The  Primary  system  is  highly  crystal- 
line and  destitute  of  fossils.  It  is  divided  into  argillaceous  slate, 
calcaieo-mica-slate,  mica-slate,  talcose  slate,  Green  mountain  gneiss, 
gneiss  proper,  which  however  does  not  represent  the  order  of  super- 
position as  the  strata  are  involved  in  great  confusion.  The  marbles  of 
the  state  are  divided  into  three  systems,  Primary,  Taconic  and  New 
York.  There  are  few  Primary  marbles  in  the  state.  The  Taconic 
marbles  occur  throughout  the  range  of  limestone  from  Massachusetts  to 
the  north  part  of  Madison  county.  The  Taconic  system  includes  roof- 
ing slate,  Taconic  slate,  Sparry  limestone,  magnesian  slates,  Stockbridge 
limestone,  and  granular  quartz-rock. 
Adams,1"  in  1816,  includes  tin4  Taconic  and  Primary  systems  of  his 
previous  reports  under  the  general  term  Azoic  stratified  rocks,  as 
simply  expressing  the  fact  of  the  absence  of  organic  remains,  for  it  is 
not  to  be  assumed  that  the  Azoic  Taconic  rocks  are  more  ancient  than 
the  Paleozoic,  and  the  same  remarks  may  be  said  of  the  so-called  Pri- 
mary rocks,  not  a  small  portion  of  which  may  be  as  metamorphic  and 
