108 GUIDEBOOK OF THE WESTERN UNITED STATES. 
been the prospector’s constant companion in his lonely wanderings 
over these bleak ranges and his main dependence for the transporta- 
price of the metals. One of the most j years it w ras small, After 1901, how 
striking features shown by the dia- ; ever, it increased rapidly until Me 
gram is the remarkable increase in the | 1915 it was more than ae of 
value of the output of this district | the total output of the distr 
since 1902, with the exception of 1908, Thus Leadville, which ial in 1860 
the total has been due largely to the | greatest atlver-lead district this coun- 
marketing of great quantities of zinc. | try has ever produced and in 1915 be- 
In 1915 the zine amounted to $8,989,154 | came tote a ae az = rae 
out of a total of $13,839,401. The n and occurrence of t 
Figure 26 shows the: gradual de- | ores of gid bear little resem- 
cline in the production of silver from 
that at first gold formed only a small 
Sw. 
<< — 
0 500 1,000 1500 Feet 
1 
FIGURE 27 nial eres through some of the workings at Leadville, showing the oo of 
the ore to the limestone, rg ey quartzite. wp, White porphyry ; por- 
phyry ; coh Leadville lim eee: parting quartzite; wl, white Sse Ait qtz, 
lower quartzite; gr, granit a Jon bodies are indicated by cross hatching. he 
straight heavy lines se cease faults, and the arrows show the direction of movement. 
percentage of the whole but that in | from deep in the interior of the earth 
it began to oe and that in | through fissures in the breccia that 
1900 it attained maximum of | filled the throat of an old yoleano. At 
$2,500,000. Since ner time it has | Lea he ores repla stone, 
wee 
put has been very regular, its value | an adjacent ecectalte. ‘This re 
amounting to about beige a year. | lation is shown in figure 27, which 
tesbetie district. _ production of | were brought to Pf place by waters 
this metal first noticeable in | ascending from great depth or by 
the returns for seg aA for a few | waters sinking down through cracks 
