OHAPTEE   VII. 
EASTERN  UNITED  STATES. 
SECTION  I.      THE  NEW  ENGLAND   STATES. 
LITERATURE   OF   MAINE. 
Jackson/  in  1837,  observed  granite,  gneiss,  and  mica-schist  at  many 
localities.  At  one  place  schistose  fragments  occur  in  syenite,  which 
indicates  that  the  syenite  has  been  thrown  up  in  a  melted  state  since 
the  deposition  and  induration  of  the  argillaceous  and  talcose  slates 
included.     Dikes  very  frequently  cut  the  fossiliferous  horizon.     • 
Hitchcock2  (Edward)  in  1837,  describes  a  rock  succession  at  Port- 
land as  consisting  from  the  base  upward  of  (1)  granite;  (2)  gneiss;  (3) 
talcose  and  mica-slates,  with  quartz-rock;  (4)  hornblende  slate;  (5) 
limestone;  (6)  plumbaceous  mica-slate;  (7)  pyritiferous  mica-slate. 
The  latter  has  the  aspect  of  a  graywacke-conglomerate,  being  filled 
with  distinct  rounded  masses  of  quartz  rock.  It  is  really  a  mica-slate 
conglomerate.  The  series  are  in  a  vertical  position  and  the  whole  are 
cut  by  greenstone  dikes. 
Jackson,3  in  1839,  includes  in  the  Primary  rocks  of  Maine  the  gran- 
ites, gneiss,  talcose  slate,  and  argillaceous  slate.  The  transition  rocks 
are  a  great  formation,  which  includes  slates,  limestones,  fine  gray- 
wackes,  and  coarse  conglomerates.  It  is  also  fossiliferous.  At  one  place 
mica- slate  is  thrown  aside  by  intrusive  granite. 
Hitchcock4  (Chas.  H.),  in  1861,  divides  the  unfossiliferous  rocks 
into  Stratified  or  Azoic  and  Laurentian.  With  the  latter  are  placed 
granitic,  trappean,  and  Archean  rocks.  The  Azoic  rocks,  which  may 
be  in  age  Laurentian  to  Carboniferous,  include  gneiss,  mica- schist, 
quartz-rock  and  conglomerate,  jasper,  siliceous  slate,  and  hornstone.  The 
quartz-rocks  and  conglomerates  are  associated.  At  one  place  a  con- 
glomerate has  elongated  pebbles  which  indent  each  other,  which  is 
evidence  that  they  must  have  been  in  a  plastic  condition.  Metamor- 
phism  may  even  produce  granite  and  gneiss  by  aqueo-igneous  fusion. 
The  syenites  containing  fragments  of  schist  and  trap,  described  by 
Jackson,  are  believed  to  be  metamorphosed  conglomerates,  the  included 
pebbles  of  which  have  preserved  their  original  shapes.  The  foliation 
of  the  metamorphic  rocks  generally  correspond  with  the  planes  of  strat- 
ification, but  may  cross  the  strata  like  cleavage  planes.  The  trap  dikes 
are  believed  to  be  eruptive. 
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