114  CONTRIBUTIONS    TO    ECONOMIC    GEOLOGY,   L906,    PART    I. 
rock  on  which  it  is  found.     Specimens  from  the  Cay  wood  No.  1  claim] 
have  been  tested  by  George  Steiger  in  the  laboratory  of  the  United 
States  Geological  Survey,   and   are  reported   by  him  as  containing] 
uranium  and  vanadium  and  as  being  probably  carnotite.     There  is 
practically  no  doubt  that  the  mineral  is  actually  carnotite,  as  it  has! 
already  been  so  determined  by  a  number  of  authorities  who  have! 
examined  material  from  this  locality.     Material  for  a  complete  analy- 
sis has  now  been  sent  to  the  Survey  laboratory  and  will  probably  bdj 
studied  later. 
The  specimens  collected  were  the  better  pieces  among  those  lying 
out  on  the  dump,  together  with  some  hammered  from  the  ledges  near 
their  surface  outcrop.  The  ore  shows  very  clearly  the  original  woody 
structure  in  the  silicified  gangue,  which  is  now  of  a  rusty-brown  color 
and  filled  with  seams  and  cracks.  Some  small  pieces  of  coal  were  also 
found,  but  these  were  fragments  or  small  patches  and  not  a  continuous  • 
seam.  As  is  explained  more  fully  on  page  116,  the  yellow  carnotite^ 
is  evidently  a  surface  coating,  filling  fractures  and  impregnating  the 
neighboring  sandstone. 
A  prospect  pit  said  to  be  known  as  Caywood  No.  2  is  situated  about: 
300  yards  from  Caywood    Xo.   1    in  a  southerly  direction   along  the 
ridge  summit,  hut  about  300  feet  lower  down.     Here  the  sandstones 
showed  a  green  si  ain  for  4  or  5  feet  down  from  the  surface  of  the  ledge- 
on  the  ground,  especially  along  the  jointing  planes  in  the  rock.     This 
prospect   apparently  contained  no  yellow  ore,  but  a  streak  of  fossil' 
wood  was  exposed,  embedded  in  the  massive  sandstone,  which  carrieci;, 
much  green  stain.     This  proved  on  testing"  to  be  a  copper  stain  ancnj 
showed  no  i  race  of  vanadium  or  uranium.     The  whole  prospect   pi 
was  in  massive  though  much  broken  sandstone.     Below  the  Oaywoool 
No.  '2  down  the  ridge  to  the  bed  of  Coal  Creek  fragments  of  si!icifie< 
wood  were  noted,  apparently   marking  a  single  continuous  stratum! 
in  i  he  Dakota  ledges. 
OTHER    PROSPECTS. 
On  the  south  side  of  Coal  Creek,  along  the  southerly  continuation 
of  the  hogback  ridge  that  has  just  been  described,  another  prospe<  ij 
pit  was  found.  This  is  about  half  a  mile  in  a  straight  line  south  (I 
Coal  Creek  and  1,200  feet  or  so  above  the  main  creek  valley.  Ni 
carnotite  has  been  discovered  here,  but  the  silicified  wood  noted  it 
the  other  prospects,  as  well  as  the  associated  strata,  seemed  at  M 
time  of  visit  to  mark  this  pit  as  being  at  a  horizon  in  the  Dakotd 
ledges  almost,  if  not  exactly,  identical  with  that  of  the  prospect 
already  described.  However,  inasmuch  as  the  plotting  of  this  localil 
on  the  map  seems  to  show  its  position  as  at  some  little  distance  we>i 
of  the  main  sandstone  ridge,  the  first  conclusion  as  to  its  identity 
a  By  George  Steiger,  in  laboratory  of  United  States  Geological  Survey. 
