86 
i  OSTTRIBUTIONS    TO    ECONOMIC    GEOLOGY,  1006,  PART    I. 
Gold  rallies  of  Snake  River  placers  in  the  vicinity  of  Minidoka  clam,  as  determined  in  the 
black-sand  investigation  at  Portland,  Orcg. — Continued. 
hp 
Name  of  placer 
•         claim. 
Begihl  . 
Do. 
Do. 
Do. 
Do. 
Sample. 
Do 
Do... 
Do 
Do 
<  rol  len  Treasure 
Bar. 
<  >\V!ltT. 
W.ll.  Philbrick. 
....do 
....do 
.do. 
.do. 
.do. 
.do. 
.do. 
.do. 
.do. 
Pit 
No. 
Depth. 
From- 
To- 
Ft.  in. 
11  6 
13  0 
2  6 
4 
16 
3 
4 
4 
■> 
'< 
2 
Ft.  in. 
Per- 
Value of  orig- 
cent- 
inal gravel. 
age  of 
Value 
over- 
of 1111- 
Per 
cubic 
yard. 
size  on 
2  milli- 
meters. 
dersize. 
Per 
ton. 
51.0 
80.17 
$0.08 
$0.10 
74.  1 
.04 
.01 
.in 
72.  1 
.04 
.01 
.ni 
72.1 
.04 
.01 
.01 
48.5 
.29 
.  15 
.20 
70.0 
.  54 
.  16 
.21 
64.5 
.12 
.04 
.05 
50.0 
.21 
.  11 
.14 
51.8 
.06 
.03 
.04 
13.8 
.50 
.  28 
.36 
60.8 
.10 
.13 
52.  I 
.  12 
.06 
.08 
69.  6 
.29 
.09 
.  12 
Cumu- 
lative 
value. 
$n.03 
.00 
.02 
.01 
.04 
.09 
.01 
.09 
.01 
.18 
.09 
.04 
.08 
Detailed  records; of  cadi  of  the  sections  at  the  pits  included  in  the 
foregoing  table  arc  given  in  the  report  by  David  T.  Day  on  placer 
claims  above  the  Minidoka  dam  which  is  now  on  file  in  the  office  of  til 
Reclamation  Service  at  Washington,  D.  C,  and  from  w  Inch  the  above 
table  is  compiled. 
The  gravels  along  Snake  River  in  the  vicinity  of  Wapi,  Idaho,  have 
been  worked  by  Dunn  &  Hand,  all  of  their  workings  being  on  old 
high  bars  or  ten-aces  (part  of  which  are  now  under  water)  along  the< 
present  river  channel.  C.  II.  Hand  states  that  the  gold  here  is  a  very 
fine  Hake  gold,  and  amalgamates  readily.  The  gold  is  scattered 
through  the  gravel  but  is  usually  best  at  the  top  of  the  beds.  It 
occurs  in  heaviest  particles  in  the  oldest  bars.  The  pay  streaks  inn 
from  a  few  inches  to  6  or  7  feel  in  depth,  but  in  some  places  exceed  22 
feet,  at  which  depth  the  gold  has  run  as  high  as  22  cents  per  cubic 
yard.  Where  bed  rock  lies  at  the  shallow  depths,  say  from  6  to  8 
feet  below  the  surface,  the  pay  streak  in  some  places  rests  on  the  bed 
rock.  Occasionally  two  or  more  pay  streaks  are  encountered,  one  on 
Led  rock  and  the  other  higher  in  the  gravels  or  near  the  top.  It  is, 
however,  exceptional  to  find  the  pay  streak  on  bed  rock.  The 
bars  in  this  locality  are  very  extensive,  amounting  to  hundreds  of 
acres.  Actual  clean-up,  by  sluicing  some  thousand  of  yards,  shows  a 
value  of  a  little  more  than  20  cents  per  cubic  yard  for  souk4  million  of 
yards.  Gravels  of  much  higher  grade  occur  at  some  places  in  thin 
seams.  For  a  short  distance  these  may  run  as  hi^h  as  several  dollars 
per  cubic  yard.  The  above  averages  are,  however,  for  gravels  worked 
from  12  to  15  feet  in  depth  and  include  both  the  gravels  and  the  sur- 
face soil.  Besides  the  gold,  the  gravels  for  the  above  depths  carry 
about  three-fourths  of  1  per  cent  of  black  sand  and  other  heavy 
minerals. 
