136 FIELD CoLumMBIAN Mus—EuM—GEOoLocy, VOL. 1. 
This is an iron-stained quartz, thoroughly impregnated with 
fine-grained, light-colored, iron pyrites. 
‘¢53. Quartz, ore from the Sucre mine.”’ 
This is a colorado ore of white quartz, iron-stained in the seams, 
with inclusions of limonite and of a clay-like mineral. 
‘¢54. Quartz, ore from the Sucre mine.” 
‘¢55. Pyrites, ore from the Sucre mine.” 
‘«56. Quartz, ore from the Sucre mine.”’ 
‘¢57. Colorado ore with native gold from the Providencia mine.”’ 
‘¢58. Ore from the Estancon mine, near Santa Isabel.” 
‘¢59. [E1055.] Ore from the Estancon mine, near Santa Isabel.”’ 
This is a much-seamed white quartz, with some seams slightly 
iron-stained. The sulphides are in the form of a band, containing 
pyrite and galena, accompanied by cavities which contain a few 
pseudomorphs of limonite. There is perhaps twice as much galena 
present as pyrite, the latter appearing to be of later origin. 
‘¢60. Gneiss from the wall rock in the Santa Isabel mine.” 
‘61. [E 1056.] Quartz, ore from the Santa Isabel mine.” 
‘‘62. Quartz, ore from the Santa Isabel mine.’’ 
‘63. [E 1057.] Pyrite, ore from the Santa Isabel mine.” 
This white quartz, with stains of limonite, shows a redeposition 
of pyrites in the cubical cavities now containing limonite, from 
which an older generation of pyrite had previously been dissolved. 
A cellular pyrite partially fills cavities in the quartz, apparently left 
by a previously dissolved pyrite of much coarser crystallization. 
‘64. [E 1058.] Colorado ore with native gold from the Santa 
Isabel mine.’’ 
This is an impure yellow-stained quartz, much brecciated, with 
some kaolinized country rock attached. The quartz is schistose 
from shearing. Between some of the sheets are cellular planes filled 
with quartz crystals and loose limonite. Wire gold is found scattered 
in numerous irregular clusters over these crystals. 
“65. [E 1059.]| Colorado ore with native gold from the Santa 
Isabel mine.” 
This iron-stained brecciated quartz contains irregular cavities. 
Little free gold is visible. 
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