vanhise.]  THE    CORDILLERAS.  299 
In  the  Wasatch,  among  the  rocks  whieh  the  Fortieth  Parallel  .survey 
jalciced  as  pre-Cambrian,  the  Writer  was  able  to  find  no  rocks  which  are 
not  completely  crystalline.  An  examination  of  the  specimens  collected 
by  that  survey  showed  no  clastic  rocks.  Ill  the  Farming-ton  area  the 
crystalline  schists  and  gneisses  are  cut  by  coarse,  intrusive  granites; 
hence,  so  far  as  at  present  known,  aside  from  the  usual  fundamental 
crystalline  complex,  there  is  no  evidence  of  any  rocks  below  the  con- 
formable succession  placed  in  the  Paleozoic,  excepting  the  small  area  of 
quartzites  and  quartzose  mica-schists  at  the  foot  of  the  Cottonwood 
canyons.  The  reference  of  the  basement  complex  of  the  Wasatch  to 
the  Huronian  on  lithological  grounds  by  the  Fortieth  Parallel  Survey 
could  have  been  made  only  by  a  mistaken  conception  of  the  real  char- 
acter of  that  series.  This  complex  is  lithologieally  much  more  nearly 
like  the  crystalline  complex  of  rocks  usually  referred  to  the  Laurent  ian- 
•  The  calcareous  argillites*,  limestone,  and  the  quartzites  occurring  on 
Antelope  island  and  Promontory  ridge  are  of  a  different  lithological 
character  from  the  main  area  of  Wasatch  Archean  and  may  represent 
a  later  series  of  rocks.  To  this  series  the  Lower  Cottonwood  schists 
may  also  belong.  There  is  no  decisive  structural  evidence  in  the  nature 
of  known  contacts  showing  that  these  rocks  are  older  than  the  lower 
part  of  the  succession  which  was  referred  to  the  Paleozoic,  but  the 
latter  series  is  nowhere  so  crystalline,  and  the  fact  that  these  rocks 
were  placed  in  the  Archean  rather  than  the  Paleozoic  by  the  Fortieth 
Parallel  survey  shows  that  the  affinities  of  these  rocks  were  thought  to 
be  with  the  former.  Since  part  of  the  rocks  here  included  are  certainly 
of  clastic  origin,  it  appears  that  there  is  in  this  region  representatives 
of  the  Algonkian  system. 
Below  the  Olenellus  fauna  in  the  great  succession  of  rocks  referred 
to  the  Paleozoic  by  the  Fortieth  Parallel  survey  is  a  conformable  infe- 
rior series  of  quartzites  and  schists  about  12,000  feet  in  thickness. 
There  is  no  evidence  that  these  are  not  pre-Olenellus,  and  they  are  there- 
fore doubtfully  mapped  as  pre-Cambrian  or  Algonkian.  The  descrip- 
tions of  this  series  show  that  it  is  a  considerably  altered  one.  The  sand- 
stones have  been  indurated  to  quartzites,  and  the  mica-schist  of  Twin 
peak  is  quite  crystalline.  If  this  reference  jof  the  Wasatch  lower  quartz- 
ite  to  the  Algonkian  proves  correct,  it  stands  as  the  uppermost  series 
of  this  system,  in  a  position  equivalent  to  tin1  great  series  of  barren 
slates  of  Montana,  described  by  Davis  and  Peale  as  conformably  below 
the  Cambrian. 
SECTION  V.     NEVADA,  NORTH  OF  PARALLEL  39°  30'. 
LITERATURE. 
Schiel,38  in  1855,  states  that  in  the  Humboldt  and  other  island  moun- 
tains of  the  desert  west  of  Salt  lake  are  granites,  syenites,  quartzose 
rocks,  and  clay-slates. 
