18 GEOLOGY A^'U M1NI>G INDUSTRY OF LEADVILLE. 



product is calculated according to the mint valuation ($1.2929 per ounce 

 of silver), which, as is well known, is in the case of silver considerablv 

 higher than the fluctuating market value, and increases the value given for 

 the total product by about seven niillion dollars above that which would 

 be obtained bv using the market value, if it were possible to obtain it in 

 each case. The price of lead is assumed at 4i cents a pound as an aver- 

 age for the whole period involved : 



Production of LeadviVv mincs/rom 1^77 to 18-4, iiulueive. 



In the time that has elapsed since the census year, although, owing 

 partly to decline in value of the metals and partly to a lower average tenor 

 of the ore, the total value of the annual jiroduct has decreased, the amount 

 of ore extracted from the mines of the district has very considerably 

 increased, this having been in the census year (1879-1880) 162,241 tons, 

 and in the j-ear 1884, according- to the report of the Director of the Mint, 

 232,000 tons. 



