CARNOTITE    IN    RIO    BLANCO    COUNTY,  COLO.  117 
of  sedimentary  rocks.  No  occurrences  of  carnotite  have  been  ob- 
served or,  so  far  as  the  writer  knows,  reported  within  the  coal  field 
itself.  The  only  other  suggestion  that  can  now  be  offered  to  explain 
a  possible  source  of  uranium  and  vanadium  is  that  they  may  have 
been  derived  from  the  basalt  of  Sleepy  Cat  Mountain,  bowlders  of 
which  lie  scattered  over  the  Dakota  sandstone  ridges. 
VALUE." 
In  the  absence  of  knowledge  as  to  the  nature  and  extent  of  the 
deposits  in  depth  very  little  can  be  said  of  their  probable  commercial 
value.  An  announcement  in  the  Engineering  and  Mining  Journal  of 
March  3,  1906,  reporting  the  discovery  of  the  properties  that  have 
been  described  in  the  foregoing  pages,  stated  the  intention  of  the 
owners  to  ship  10  tons  of  ore  from  these  claims  to  Denver  for  treatment. 
It  is  not  known  whether  this  intention  has  been  carried  out  or  not,  but 
to  provide  a  sound  basis  for  an  estimate  of  values  available  the  sample 
should  represent  more  than  the  present  shallow  workings,  and,  as 
need  hardly  be  stated  here,  should  be  a  fair  average  of  the  actual  run 
of  prospecting  that  has  been  sufficiently  extensive  to  varrant  further 
commercial  development  in  case  the  values  are  found  satisfactory. 
a  An  article  in  the  Mining  Magazine  for  February,  1906,  describes  a  method  of  treating  this  ore  in  a 
commercial  way. 
