VAN  HISR.] 
EASTERN    UNITED    STATES, 
381 
Eozoic 
j  Labrador  ofiPemigewasset. 
iuperimposed  upon  a  gneiss,  as  shown  by  peculiar  erosion.  At  Sunder- 
land, East Wallingford,  Ripton,  Bristol  and  Clarksburg, Massachusetts, 
the  fossiliferous  rocks  contain  pebbles  of  a  peculiar  blue  quartz  which 
ls  derived  from  the  gneiss.  The  gneiss  is  a  northward  continuation  of 
the  Eozoic  rocks  of  New  Jersey,  the  Highlands  of  New  York  and  of 
southern  New  England.  In  Maine  the  Cambrian,  Huronian  and  Ta- 
nnic rocks  are  placed  together  and  also  the  Montalban  and  Laurentian. 
The  granite  and  trap  and  altered  slates  are  not  placed  in  the  strati, 
graphical  column.  The  gneisses  are  regarded  as  older  than  either 
bhe  Cambrian  or  Huronian.  The  pre  Silurian  rocks  of  New  Hamp- 
shire are  classified  as  follows: 
Laurentian Porphyritic  gneiss. 
f  Bethlehem  group. 
■Vtlantic  '  i.jake  Winnipiseogee  gneiss. 
)  Montalban  or  White  mountain  series. 
^Franconia  breccia. 
Conway  granite. 
Albany  granite. 
Chocorua  granite. 
Ossipyte. 
Compact  feldspar. 
Exeter  syenites, 
f  Lisbon  group. 
Huronian ;  Lyman  group. 
I  Auriferous  conglomerate, 
f  Rockingham  schists. 
I  Calciferous  mica-schist. 
Paleozoic Cambrian >  Coos  group. 
Clay  slates. 
k  Mount  Mote  conglomerate. 
The  Atlantic  system  is  proposed  to  cover  all  the  rocks  along  the  At- 
lantic coast  from  Maine  to  Alabama,  being  regarded  posterior  in  time 
go  the  Laurentian  but  anterior  to  the  Cambrian  and  later  formations. 
Walcott,85  in  1886,  places  the  Georgia  formation,  which  is  found  to 
3ontain  the  Olenellus,  in  the  middle  Cambrian,  and  the  Braintree  series 
A'  Massaehusett  bearing  the  Paradoxides  fauna  is  placed  in  the  Lower 
Cambrian. 
Walcott,36  in  1888,  in  a  consideration  of  the  Taconic,  places  the 
western  core  of  the  Green  mountains  as  pre-Cambrian,  the  bounding 
ine  being  at  a  considerable,  but  a  varying  distance  east  of  Rutland, 
Vliddlebury,  Burlington  and  St.  Albans.  All  of  the  rocks  of  western 
Massachusetts  are  regarded  as  Cambrian  or  post- Cambrian,  including 
lie  Stockbridge  limestone,  the  granular  quartz  rock,  the  magnesian 
late,  Sparry  limestone,  and  Taconic  slate.  In  northwestern  Connecti 
jut  is  an  area  of  pre-Cambrian  rocks  which  is  surrounded  by  quartzite 
eferred  to  the  Georgia  formation. 
Walcott,87  in  1889,  after  a  consideration  of  the  Cambrian  fauna 
everses  the  position  of  the  Georgia  and  Braintree  horizons,  placing  the 
after  as  Middle  and  the  former  as  Lower  Cambrian. 
