886 
PRE-CAMBEIAN    GEOLOGY   OF    NORTH   AMERICA. 
McConnell's  studies  of  the  Klondike  stratigraphy0  can  be  briefly 
summarized  as  follows: 
Moose  Hide  group — Green  igneous  rocks,  both 
massive  and  schistose. 
Klondike  series — Micaceous  and  feldspathic 
schists,  probably  altered  eruptives. 
Hunker  series — Graphitic  schists,  some  lime- 
stones, dolomites,  and  green  schists. 
Indian  River  series— Slates  and  quartz  schists 
passing  into  mica  schists,  with  some  limestone. 
Stratified  and  foliated  rocks, 
mostly  Paleozoic. 
Though  this  succession  is  by  no  means  identical  with  that  described 
by  Spurr,  100  miles  to  the  west,  it  has  some  similarity.  McConnell's 
basal  rocks,  the  Indian  River  "  series,"  resemble  the  Birch  Creek 
schist,  and  these  are  overlain  by  the  Hunker  "  series,"  which  are  not 
unlike  the  Fortymile  group.  The  Klondike  "  series  "  appears  to  be 
made  up  of  altered  intrusives. 
The  writer  b  has  described  some  white  crystalline  limestones,  asso- 
ciated with  phyllites,  which  outcrop  along  the  lower  course  of  White 
River  under  the  name  Xasina  "  series,"  and  the  provisional  correlation 
with  the  Fortymile  group  still  stands.  McConnell c  adopted  the  name 
Xasina,  and  in  a  personal  letter  states  that  he  has  traced  this  same 
belt  of  rocks  far  to  the  south  and  inclines  to  the  belief  that  they 
may  be  found  to  be  the  equivalent  of  the  sediments  included  by  Daw- 
son in  his  Shuswap  "  series." 
In  northern  Alaska  the  pre-Devonian  succession  is  hardly  as  well 
established  as  the  multiplicity  of  formation  names  might  lead  the 
casual  reader  to  infer.  Schrader,*7  after  his  first  season  in  this  district, 
where  he  explored  the  Chandalar  and  Koyukuk  basins,  published  the 
following  section :  Its  basal  member  is  the  "  Rapid  "  schist,  and  con- 
sists of  a  biotite  schist,  often  carrying  garnet  and  other  metamorphic 
minerals.  The  published  description  does  not  show  any  marked  dif- 
ference between  these  schists  and  those  associated  with  Schrader's 
so-called  basal  granite.  The  next  younger  horizon  is  termed  "  Am- 
phibolite  schist,"  and  is  described  as  fine  grained  and  pale  green  in 
color.  As  this  formation  is  defined  it  also  includes  a  quartz-mica 
schist   and   does  not  appear  to  be  sharply   differentiated   from  the 
a  McConnell,  R.  G.,  The  Klondike  region  :  Ann.  Rept.  Geol.  Survey  Canada,  new  ser.,  vol. 
12,  1899,  pp.   18a-20a. 
b  Brooks,  Alfred  H.,  Reconnaissance  in  Tanana  and  White  River  basins:  Twentieth 
Ann.  Rept.  U.  S.  Geol.  Survey,  pt.  7,  1900,  pp.  465-466.  In  another  report,  entitled 
A  reconnaissance  from  Pyramid  Harbor  to  Eagle  City,  Twenty-first  Ann.  Rept.  U.  S. 
Geol.  Survey,  pt.  2,  1900,  pp.  357—358,  the  writer  grouped  all  the  gold-bearing  rocks 
together  under  the  name  "  Kotlo  series,"  which  would  include  the  Birch  Creek,  Forty- 
mile,  and  Rampart  groups  ;  but  now  that  more  detailed  studies  have  been  made,  the  name 
"  Kotlo  "  can  be  entirely  eliminated  from  the  stratigraphic  nomenclature. 
c  Summary  Rept.  Geol.  Survey  Canada  for  1900,  p.  41. 
d  Schrader,  F.  C,  A  reconnaissance  along  Chandlar  and  Koyukuk  rivers  :  Twenty-first 
Ann.  Rept.  U.  S.  Geol.  Survey,  pt.  2,  1900,  pp.  472-476. 
