63 
The visitor should now pass to the eastern end of the hall 
:and not the following special groups in the center: 
K. — Silver, lead and copper ore, Cordillera Hill silver mine. 
Peel wood, New South Wales. 
L. — Gold and silver ore, British Columbia. 
M. — Gold ore. A group of large specimens from various 
localities. 
N. — Zinc-lead ore, Laurium, Greece. 
O. — Copper-silver ore, Leadville, Colorado. 
CASE P. — Group of large specimens of gold ores from 
American localities : 
Q. — Gold-copper-silver ore, Ouray County, Colorado. As- 
says copper, 28 per cent.; silver, 160 oz. per ton. 
R. — Auriferous quartz, San Miguel County, Colorado. As- 
says average $6 to $8 gold per ton. 
S. — Gold ore. A group of large specimens of refractory gold 
ores. 
T. — Block of ore from 40 foot level of the Back Creek Silver 
and Gold Mine, New South Wales. 36 tons yielded 3,406 oz. 
silver, and gold at the rate of 15 dwt. per ton. 
U. — Gold ore, Alma. Park County, Colorado. Assays $25 
per ton. 
WALL CASES S, V, and W. — Large specimens of silver 
and lead ores. 
HALL 77. 
West Dome. 
Beneath the center of the dome stands a statistical column, 
giving the bulk of each product of the mines of the United 
States in 1892, for one second of time. Multiplying this by the 
number of seconds in a year (31,536,000) will give the annual 
product. This column was built according to data given by the 
United States Geological Survey. In the four niches are pyra- 
mids of ore, containing: No. 1— Gold and Silver Ores; No. 2— 
Tin Ores; No. 3— Iron Ores; No. 4 — Copper Ores. 
The four large specimens surrounding the column are respect- 
ively: No. 5— Iron Ore; No. 6— Silver Ore; No. 7-— Iron Ore; 
No. 8 — Nickel Ore. 
