van  .use,]  EASTEKN    UNITED    STATES.  349 
Hitchcock  (Chas.  H.),5  iu  1862,  describes  the  rocks  of  the  southern 
part  of  the  state  as  granite  and  syenite,  gneiss  and  mica-schist,  saccha- 
roidal  Azoic  limestone,  quartz-rock,  (Taconic),  Eolian  limestone,  etc. 
Presumably  the  granite  and  syenite,  the  gneiss  and  mica-schist,  and 
Azoic  limestone  are  Primitive.  In  the  Kennebec  valley  are  found  in- 
terstratified  limestones  and  slates,  the  cleavage  of  which  is  almost 
transverse  to  the  bedding,  so  that  it  is  only  possible  to  get  at  the  true 
direction  of  lamination  by  following  the  limestone  belts.  At  one  place 
is  an  abrupt  change  from  mica-schist  to  granite.  A  red  conglomerate 
rests  uncomformably  upon  a  slate  at  Woodstock. 
Hitchcock  (OhAS.  H.),6  in  1874,  describes  at  Portland  three  groups 
of  rocks,  the  oldest  of  which  is  the  Huronian.  In  this  system  are  green 
talcose  schists,  hornblendic  schist,  micaceous  and  plumbaceous  schist, 
and  other  varieties.  They  are  referred  to  the  Huronian  on  the  ground 
that  such  rocks  are  typical  of  this  period,  and  continuity  of  mineral 
character  indicates  similarity  of  age  till  otherwise  proved. 
Huntington,7  in  1878,  describes  the  region  about  the  headwaters  of 
the  Androscoggin  river.  The  rocks  are  classified  as  Laurentian,  Hu- 
ronian, and  Paleozoic.  In  the  Laurentian  is  gneiss,  containing  lime- 
stone. In  the  Huronian  are  White  mountain  gneisses  and  schists, 
mica- schists,  with  staurolite,  chloritic  and  whitish  argillitic  mica- schists, 
sandstone-schists,  diabase,  diorite  with  serpentine,  argillitic  mica- 
schists  with  staurolite,  and  Eangely  conglomerates.  In  the  Eangely 
conglomerate,  when  freshly  broken,  every  portion  of  it  except  the  peb- 
bles resembles  in  all  respects  the  staurolitic  schist.  Going  across  the 
stratification  are  places  where  the  pebbles  are  wanting,  or  have  been 
so  changed  that  they  are  not  apparent,  although  locally  the  fragments 
of  the  conglomerate  are  a  foot  in  diameter.  Granite,  diorite,  and  fels- 
ite  are  placed  among  the  eruptive  rocks. 
Shaler,8  in  1889,  describes  the  rocks  of  mount  Desert.  The  island 
consists  of  a  central  mass  of  hornblende-granite  and  a  succession  of 
sedimentaries  on  the  north  and  south  sides.  About  the  massive  core 
are  the  following  series :  The  Sutton  island  series  of  highly  metamor- 
phosed clay-slates,  quartzites,  bedded  felsites,  and  associated  traps; 
the  Cranberry  island  series,  essentially  the  same  as  the  Sutton  island 
series,  with  many  beds  of  volcanic  ash ;  the  Schooner  head  series  of 
contorted  argillaceous  schists,  shales,  and  the  associated  injected 
rocks;  the  Bar  harbor  series  of  thick-bedded  flaggy  slates  and  asso- 
ciated bedded  felsites  and  quartzites,  with  numerous  injections  of 
igneous  rocks;  and  the  Bartletts  island  series  of  contorted  schists, 
with  frequent  beds  of  quartzites,  which  often  assume  a  gneissic  aspect 
with  the  associated  injections  of  igneous  rocks.  The  great  central 
mass  of  granite  is  said  to  be  essentially  a  dike.  In  approaching  the 
central  granite  the  amount  of  granitic  dike  injections  in  the  sedimen- 
tary series  greatly  increases,  and  in  the  sedimentary  rocks  are  found 
numerous  dikes  of  granite.     No  two  of  the  various  sedimentary  series 
