290 
CONTRIBUTIONS    TO    ECONOMIC    GEOLOGY,  1904.         [bull.  200. 
Table  showing  production  of  lead,  silver,  and  gold  in  the  Coeur  d'Alene  district 
(Shoshone  County)  from  1884  to  1904. 
Year. 
1884. 
1885. 
1886. 
1887. 
Lead, 
in  tons 
of  2.000 
pounds. 
1890. 
L891 
1892. 
1893. 
1894. 
1895. 
1896. 
1898 
1899 
1900 
1901 
1902... 
1903 
1904 
b 1,500 
&5,980 
&8.000 
617,500 
^27,500 
b 33, 000 
<'27,839 
c 29, 563 
c 30, 000 
e 31, 000 
d  37, 250 
d 57, 777 
d 56, 339 
rf50,006 
d 81, 535 
<*68,953 
''74, 739 
''103,691 
el07,560 
Value  of 
lead. 
$138,900 
538,200 
705,600 
1,333,500 
2,392,500 
2,857,800 
2,266,094 
2,424,166 
1,968,000 
2,008,800 
2,212,650 
4,159,944 
4,225,425 
4,440,533 
7,207,094 
6,026,492 
6,091,228 
8, 772, 258 
9,271,672 
Total  and 
average.   849,732 
,040,856 
Silver, 
in  fine 
ounces. 
116,246 
340,000 
554,000 
1,095,265 
1,499,663 
1,825,765 
1,195,904 
1,983,561 
2,343,314 
2,471,300 
3,163,657 
3,756,212 
3,521,982 
2,737,218 
5,261,417 
4,339,296 
5,033,928 
5,471,620 
^6, 141, 426 
52,831,774 
Value  of 
silver. 
$115,664 
332,520 
520,760 
1,025,168 
1,574,646 
1,803,856 
1,045,220 
1,529,614 
1,485,661 
1,626,115 
2,132,304 
2,264,996 
2,070,925 
1,645,068 
3,262,078 
2,603,577 
2,657,914 
2,954,674 
3,512,895 
34,163,655 
Gold, 
in  fine 
ounces. 
12,500 
18,220 
8,823 
7,367 
10,250 
8,433 
8,000 
10,000 
11,000 
14, 748 
17,531 
18,439 
17,369 
16, 404 
13,011 
8,602 
5, 754 
4,915 
4,761 
7,651 
c7,000 
230, 778 
Value  of 
gold. 
$258,375 
376,607 
182,371 
152,276 
211,867 
174,310 
165,360 
206, 700 
227.370 
304,841 
362,365 
381,134 
359,017 
339,070 
268,937 
177,803 
118, 9&5 
101,593 
98, 410 
158,146 
144,690 
4, 770, 177 
Value  of 
total  me- 
tallic prod- 
ucts. 
Ratio 
of  sil- 
ver to 
lead, 
by 
weight. 
$258, 375 
376,607 
436,335 
1,022,996 
1,438,227 
2,532,978 
4,132,506 
4,868,356 
3,538,684 
4,258,621 
3,816,026 
4,016,049 
4,703,971 
6,764,010 
6,565,287 
6,263,404 
10,588,707 
8,731,662 
8,847,552 
11,885,078 
12,929,257 
107,974,688 
Ounces 
of  sil- 
ver to 
each 
unit  of 
lead.« 
1  :  384 
1  :515 
1:422 
1:466 
531 
1:679 
1:440 
1:373 
1:366 
1  :  343 
1  :448 
1  :466 
1:  533 
1:452 
1 :  463 
1 :  433 
1:  552 
1  :  511 
1  :473 
0. 77 
.56 
<U 
a  A  "unit"  of  lead  is  1  per  cent  to  the  ton  of  ore,  or  20  pounds. 
b  Reports  of  the  Director  of  the  Mint  upon  the  production  of  the  precious  metals  in  the  United  I 
States. 
'•Estimated. 
rfThe  Mineral  Industry:  Its  statistics,  technology,  and  trade  in  the  United  States  and  othei 
countries.    New  York. 
'Reported  to  Engineering  and  Mining  Journal  of  January  5,  1905,  by  Stanly  A.  Easton. 
GENERAL  CHARACTER  AND    DISTRIBUTION    OF  THE    ORE 
DEPOSITS. 
The  ore  deposits  of  the  Coeur  d'Alene  district  may  be  divided  witl 
reference  to  metallic  contents  into  three  classes:  (1)  Lead-silvei 
deposits;  (2)  gold  deposits,  and  (3)  copper  deposits.  The  lead 
silver  deposits  are  in  general  metasomatic  fissure  veins,  formed  ii 
greater  part  by  replacement  of  siliceous  sedimentary  rocks  alonj 
zones  of  Assuring.  They  consist  essentially  of  galena  and  siderite 
The  gold  deposits  comprise  bed  veins,  fissure  veins,  and  placer; 
formed  in  at  least  two  periods.  The  gold-bearing  veins  consis 
essentially  of  quartz  carrying  free  gold  and  auriferous  sulphides 
The  copper  deposits  include  impregnations  along  certain  quartzil 
beds  and  metasomatic  fissure  veins.  The  impregnated  quartzite  onl|] 
has  produced  copper  on  a  commercial  scale. 
