va%  msE.l  EASTERN    UNITED    STATKS.  379 
granites  to  the  finest  and  most  uniform  schist  the  structure  is  charac- 
terized by  a  parallel  arrangement  of  the  mineral  constituents.  Con- 
tinual alternations  were  observed  of  series  of  granitic,  micaceous,  horn- 
blendic  and  various  other  formations.  The  trap  rocks  occurring-  in  the 
primary  and  secondary  formations  are  so  near  alike  that  they  can  not 
be  separated,  but  in  the  primary  rocks  there  is  no  conformity  between 
the  traps  and  the  adjacent  formations,  such  as  prevails  in  the  secondary. 
Dana,78  in  1872,  states  that  the  quartzite  of  Canaan  outcrops  in  six 
exposures,  is  unconformably  below  the  limestone,  and  its  jointing, 
uplifting1  and  consolidation  took  place  before  the  latter  was  deposited. 
GENERAL  LITERATURE. 
DANA,79  in  1877,  maintains  that  the  conformable  succession  in  Berk- 
shire county,  Massachusetts,  and  in  Vermont  are  the  same,  being  (1)  lime- 
stones and  schists;  (2)  quartzites  and  schists;  (3)  quartzites  and  lime- 
stones; all  conformable.  The  Taconic  range  of  Berkshire  is  probably 
Upper  Trenton  or  Hudson  river  or  Cincinnati.  There  are  frequent 
abrupt  transitions  between  the  quartzite  and  gneiss  which  are  believed 
to  represent  transitions  from  sand  deposits  to  mud  deposits  in  the  old 
seas. 
Hitchcock,  (C.  H.), 80  in  1879,  describes  the  Atlantic  system  as  in- 
cluding the  highlands  of  the  Atlantic  ocean  between  Newfoundland  and 
the  Carolinas,  comprising  the  Terranovan,  confined  to  Newfoundland 
and  Nova  Scotia;  the  Montalban,  with  Green  mountain  branch,  in 
which  is  the  White  mountains;  and  the  Carolina  or  Southern,  which 
culminates  in  the  Black  mountains.  The  rocks  of  the  system  were 
deposited  in  a  Laurentian  basin  with  the  Adirondack^  on  the  west  and 
the  ancient  gneisses  of  eastern  Massachusetts  on  the  east. 
Dana,81  in  1880,  finds  that  the  western  and  easternhalves  of  the  Green 
mountain  area  are  one  orological  system,  the  rocks  being  similar,  and 
all  are  of  Lower  Silurian  age.  With  these  belong  part  of  the  central 
mountain  section.  In  view  of  these  various  considerations  the  evi- 
dence, although  not  yet  beyond  question,  is  manifestly  strong  for 
embracing  the  whole  region  between  the  Connecticut  and  the  Hudson 
(and  to  an  unascertained  distance  beyond)  within  the  limits  of  the  Green 
mountain  synclinorium. 
Dan  A, 32  in  1884,  finds  that  the  schistose  rocks  constituting  the  Ta- 
conic range  grade  from  north  to  south  from  feebly  crystalline  argillite 
and  hydromica-sehist  to  coarse  grained  mica-schist,  garnetiferous  and 
staurolitic.  The  eastern  and  western  limestone  belts  blend  with  one 
another  through  the  low  regions.,  cross  the  Taconic  line,  and  prove  the 
two  to  be  one  formation.  The  limestone  passes  underneath  the  schist 
of  the  Taconic  range  and  outcrops  on  its  east  and  west  sides  on  opposite 
sides  of  the  synclinal.  The  limestones  which  constitute  thelower  part  of 
the  Taconic  system  contain  fossils,  which  designate  it  as  Lower  Silurian ; 
hence  the  schists  of  the  Taconic  are  later  than  Silurian  age  and.  prob- 
