CHAPTER  IX. 
NEW  ENGLAND. 
SECTION  1.     MAI]N"E. 
SUMMARY  OF  LITERATURE. 
Jackson,1  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. 
Hitchcock  (Edward),2  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  is  in  a  vertical  position  and  the  whole 
is  cut  by  greenstone  dikes. 
Jackson,3  in  1839,  includes  in  the  Primary  rocks  of  Maine  the 
granites,  gneiss,  talcose  slate,  and  argillaceous  slate.  The  Transition 
rocks  are  a  great  formation,  which  includes  slates,  limestones,  fine 
graywackes,  and  coarse  conglomerates.  It  is  also  fossiliferous.  At 
one  place  mica  slate  is  thrown  aside  by  intrusive  granite. 
Hitchcock  (C.  H.),4  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 
conglomerate  has  elongated  pebbles  that  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  in- 
cluded pebbles  of  which  have  preserved  their  original  shapes.  The 
foliation  of  the  metamorphic  rocks  generally  corresponds  with  the 
planes  of  stratification,  but  may  cross  the  strata  like  cleavage  planes. 
The  trap  dikes  are  believed  to  be  eruptive. 
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