NEW   ENGLAND.  555 
stones,  with  intercalated  bands  of  siliceous  limestones.  There  are  also 
here  contained  stratified  diorites,  diabases,  and  hornblende  rocks. 
The  porphyry  which  occurs  connected  with  the  Coos  and  Huronian 
penetrates  the  rocks  with  which  it  comes  in  contact,  and  the  intrusive 
character  can  not  be  doubted.  Outcrops  of  granites  and  granitoid 
gneisses  have  a  wide  extent,  a  part  of  them  being  regarded  as  genuine 
eruptive  granites,  since  they  intersect  the  schists  in  numerous  veins 
and  beds.  The  basic  dikes  are  the  latest  of  all,  cutting  the  granites 
and  intersecting  the  schists  at  many  places. 
Hitchcock  gives  the  formations  of  the  White  Mountain  district  as 
follows,  in  ascending  order:  (1)  Porphyritic  gneiss;  (2)- Bethlehem 
gneiss;  (3)  Berlin  or  Lake  gneiss;  (4)  Montalban  group;  (5)  Fran- 
conia  breccia;  (G)  Labrador  system  or  Peinigewasset  series  of  gran- 
ites, ossipytes,  compact  feldspars,  etc.;  (7)  syenite;  (8)  andalusite 
slates;  (9)  Pequawket  or  Mount  Mote  granite.  The  three  first  are 
regarded  as  metamorphic,  although  the  stratification  is  destroyed. 
The  Montalban  group  includes  granitic  gneiss,  mica  schist,  and  quart  z- 
ite.  The  granitic  gneiss  sometimes  sIioavs  no  visible  mark  of  strati- 
fication, as  in  the  Concord  granite,  although  the  whole  is  regarded  as 
metamorphic.  An  unconformity  is  inferred  between  the  Montalban 
schists  and  the  porphyritic  gneiss  on  account  of  the  divergence  in  the 
strike  of  the  two  groups.  Eruptive  granite  is  found  in  the  Montalban 
schists.  The  Franconia  breccia  is  placed  later  in  the  chronological 
scale  than  the  Montalban  group,  because  it  is  the  impression  of  the 
author  that  he  has  seen  Montalban  fragments  in  this  rock.  The  Lab- 
rador system  is  considered  as  the  probable  equivalent  of  the  Labrador 
system  of  Logan  and  Hunt.  It  includes  the  Conway  granite,  Albany 
granite,  Chocoriia  granite,  ossipyte  or  labradorite  rocks,  and  various 
compact  and  crystalline  feldspars  or  porphyries.  The  relations  of  the 
Albany  granite  and  the  andalusite  slate  do  not  show  that  the  under- 
lying granites  are  certainly  not  sediments,  although  they  have  been  so 
thoroughly  metamorphosed  as  to  have  lost  their  lines  of  original 
bedding;  but  the  evidence  in  favor  of  their  eruption  since  the  depo- 
sition of  the  andalusite  slates  is  increasing.  The  slates  are  twisted 
and  broken  in  many  places,  the  fragments  being  cemented  together  by 
a  granitic  paste:  also,  fragments  of  slate  occur  embedded  in  the  un- 
derlying granite.  The  Labrador  group  is  found  in  seven  areas.  The 
Labrador  rocks  lie  unconformably  upon  the  upturned  edges  of  the 
Montalban  gneisses,  the  discordance  varying  from  45Q  to  70°.  Por- 
phyry occurs  in  this  system,  which  is  regarded  as  intrusive.  Syenite 
has  a  rather  widespread  occurrence.  The  andalusite  slates  are  re- 
garded as  the  equivalent  of  the  Coos  series,  but  they  arc  similar  to 
the  Huronian  system.  The  Pequawket  series  i-  regarded  as  late 
eruptives.  The  stratigraphic  order  in  the  White  Mountains  is  finally 
concluded  to  be  as  follows:   (1)  The  Laurent ian,  represented  by  the 
