790  PRE-CAMBRIAN    GEOLOGY   OF   NORTH   AMERICA. 
by  Powell  to  be  12,500  feet  thick,  and  called  the  "Uinta  group." 
These  rocks  consist  of  shales,  red  sandstones,  and  quartzites.  The 
whoJe  is  exceedingly  ferruginous  and  contains  seams  of  clay  iron- 
stone. While  much  time  has  been  spent  by  Powell  and  others  in  the 
search  for  fossils,  none  have  been  found. 
The  basal  rocks  of  the  Uinta  Mountains  have  long  been  regarded  as 
comprising  a  small  area  along  Red  Creek  Canyon,  in  the  eastern  part 
of  the  uplift.  Here  the  red  "  Uinta  "  quartzite,  with  low  dip,  rests 
with  apparent  unconformity  upon  steeply  dipping  white  quartzitic 
and  micaceous  rocks,  which  in  hand  specimen  look  like  quartzite,  but 
under  the  microscope  resemble  granite.  Possibly  they  are  highly 
metamorphosed  quartzites.  With  them  are  dark  interstratified  horn- 
blende schists,  which  resemble  dikes  of  intrusive  rocks.  While  actual 
contact  is  not  exposed,  the  difference  in  attitude  and  metamorphism 
between  the  "  Uinta  "  quartzite  and  underlying  rocks  has  been  re- 
garded as  evidence  of  unconformity.  Weeks  has  recently  suggested 
that  the  lower  rocks  are  really  to  be  correlated  with  the  upper  part 
of  the  "  Uinta  group  "  and  that  the  relations  are  to  be  explained  by 
folding  and  thrust  faulting,  he  having  traced  certain  beds  of  the  sup- 
posed lower  rocks  directly  into  the  "  Uinta  group." 
Above  the  "  Uinta  "  quartzite  is  the  Lodore  shale,  regarded  as  Car- 
boniferous by  Powell,  but  later  referred  to  the  Cambrian  by  Weeks. 
Powell  and  White  regarded  the  Lodore  shale  as  unconformable  upon 
the  "  Uinta  "  quartzite,  but  this  also  is  questioned  by  Weeks,  who  re- 
gards the  two  formations  as  essentially  conformable. 
The  "  Uinta  "  quartzite  wTas  referred  to  the  Carboniferous  by  the 
geologists  of  the  Fortieth  Parallel  Survey,  but  has  since  been  generally 
.regarded  as  pre-Cambrian  because  of  lack  of  fossils  and  inferior  po- 
sition, this  being  the  recent  conclusion  of  Weeks,  Berkey,  and  Em- 
mons.    It  is  probably  to  be  correlated  with  the  Belt  series  of  Montana. 
Wasatch  Mountains. — In  the  Wasatch  Mountains  a  granite-gneiss- 
schist  basement "  complex  that  is  typical  of  the  Archean  constitutes 
a  broad  belt  in  the  northern  part  of  the  area.  The  schists  and 
gneisses  are  cut  by  pegmatitic  granite  veins  in  the  most  irregular 
manner.  For  instance,  in  the  lower  part  of  Sawmill  Canyon  the 
complex  is  a  series  of  schists.  In  going  up  the  canyon  granite  begins 
to  appear,  cutting  the  schists,  and  becomes  more  and  more  promi- 
nent, until  it  is  the  most  abundant  material.  It  is  here  exceedingly 
coarse,  and  the  whole  appearance  is  that  of  an  intrusive  which  has 
cut  the  schists  and  gneisses  by  numerous  apophyses. 
Resting  unconformably  upon  this  Archean  complex  is  a  great  series 
of  sedimentary  rocks.  These  consist  of  mica  slates,  mica  schists, 
argillite,  and  intercalated  siliceous  schists,  800  feet  thick ;  above  these 
is  a  great  quartzite  formation  12,000  feet  in  thickness;  conformably 
above  the  quartzite  are  250  feet  of  shales,  which  according  to  Walcott 
