44 
CONTRIBUTIONS    TO    ECONOMIC    GEOLOGY,  1904.        [bull.  260. 
SUMMARY. 
Summing  up  these  statements,  the  following  estimate  represents 
the  probable  division  of  the  silver  product  for  1904: 
Source  of  production  of  silver  in  190J/. 
Placers   
Quartzose  gold  and  silver  ores : 
Pre-Oambrian  quartz  veins 70,000 
Mesozoic  quartz  veins  (Pacific  coast  belt) 800,000 
Tertiary  quartz  veins  (Rocky  Mountains  and  Great 
Basin) 11,  000,  000 
Fine  ounces. 
64,000 
■  11,939,000 
Copper  ores 18,600,000 
Lead  ores 23,000,000 
Total 53,603,000 
The  market  price  of  silver  has  gradually  increased  during  the  year 
from  57  cents  per  ounce  in  January  to  61  cents  in  December. 
Source  of  production  of  gold  and  silver  in  190 Ji. 
Gold. 
Silver. 
Placers 
Fine  ounces. 
619,700 
Fine  ounces. 
64, 000 
Quartzose  gold  and  silver  ores: 
Pre-Cambrian  quartz  veins 
Mesozoic  quartz  veins  (Pacific  coast  belt) . . 
264, 000 
1,045,000 
1.727,000 
79, 000 
860, 000 
Tertiary  quartz  veins  (Rocky  Mountains  and  Great 
Basin) 
11,000,000 
Total -. 
3,036,000 
11,939,000 
Copper  ores . 
208, 000 
222, 500 
18, 600, 000 
Lead  ores. 
23, 000, 000 
Total . 
4, 086, 200 
53, 603, 000 
