226 GEOLOGY OF ASPEN MINING DISTRICT, COLORADO. 
Calcite is very common, and in many low-grade ores the dolomite of the 
unreplaced country rock forms the chief gangue material. 
COMPOSITION OF ORES. 
In order to get at the average composition of the ores of Aspen, 
nearly four hundred assays of shipments were obtained, representing ores 
from nearly every mine in the district. Hach of these assays is a compar- 
atively exact average of many tons of ore, this average being obtained 
before analysis by a mechanical process at the sampler. These different 
analyses were again added together and averaged. Since the ores have a 
wide range in point of elevation, varying from 10,800 feet and over in 
Tourtelotte Park to 7,400 feet or lower in the deep workings of the Mollie 
Gibson and Smuggler, the different analyses were tabulated and arranged 
according to elevation, in eighteen distinct zones, each zone being 200 feet 
in thickness. Thus the average analysis given for 7,400 feet includes all 
the ores from between 7,300 and 7,500 feet; that given for 7,600 feet 
included the ores from 7,500 to 7,700 feet, and so on, 
Table showing average composition of Aspen ores, arranged according to elevation. 
Elevation.| @i03. | (Gads. | CFes0s). | (Bas0). | Gay. | "B" | Gb): aay 
Feet. Per cent. Per cent. Per cent. Per cent. Per cent. | Per cent. | Per cent. | Oz. per ton. 
7, 400 23.2 13.1 1.8 12.6 ae | Ie rae 17.5 460.0 
7, 600 19.7 17.3 2.7 13.3 2.6 2.6 5.6 234. 6 
7, 800 92 13.2 4.3 20.8 1.9 3.5 16.3 39.5 
8, 000 17.4 17.5 5.5 25.6 1.8 5.2 1.8 59.3 
8, 200 9.9 10.3 4.5 14.5 3.2 5.2 Beil 56.6 
8, 400 |. 10.1 28. 4 2.4 3.5 1.5 1.0 3.8 25.38 
8, 600 12.8 28.3 3.3 2.0 1.0 3.0 2.4 52.0 - 
8, 800 17.1 23.5 6.4 11.9 1.3 1.8 10.8 36.5 
9, 000 10.3 23.8 4.5 1.3 4 7 4.5 26.5 
9, 200 19.8 21.4 6.2 5.5 BON ae Wetec 10.4 51.3 
9, 400 33. 1 12.7 6.4 Te 3.7 5.7 3.0 26.0 
9, 600 22.6 8.7 10.1 28.7 1.9 3.90 2.9 49.8 
9, 800 382.8 10.8 6.5 23.2 1.4 2.1 8 71.9 
10, 000 23.0 11.1 8.9 24.2 2.1 8 4.4 51.0 
10, 200 37.6 14.8 4.9 16.4 1.5 9 2.4 35.6 
10, 400 27.3 7.5 10.3 21.8 3.2 6.6 6.7 62.5 
10, 600 BY) |jeceseoeeas|Facccorase SOND Se Seek Sea tally eee | meee rea 27.3 
10, 800 28.5 12.8 4.4 31.0 | Trace. 1.0 6.0 36.7 
