Mar. 1899. THE ORES OF COLOMBIA—NICHOLS, uae 
‘* 200, Pyrite and brongniartine, gold ore from the Morisco 
mine.”’ 
‘301. Gold ore from the Morisco mine.” 
‘302, [E 1086.] Galena, /ahlerz (tetrahedrite) and blende 
from the Contento silver mine.” 
The gangue is a decomposed trachyte. 
“303. [E 1087.] Galena, fax/erz (tetrahedrite) and blende, 
siver ore from the Contento mine.” (Like No. 302.) 
*©304. [E 1088.] Galena, fahlerz (tetrahedrite) and blende, 
silver ore from the Contento mine.” 
It is a compact mass of sulphides. 
‘©305. [E. 10g90.] Blende, schezderz from the Contento silver 
mine.”’ 
In appearance this specimen is much like some which occur 
in southwest Missouri. The blende occurs as a cement in a breccia 
of a chert-like quartz. Where crystals have formed, they are of the 
bright red variety, known in the Missouri zinc districts as ‘‘ruby jack.”’ 
‘©3206. Blende, silver ore from the Contento mine.” 
The blende occurs as a cement in a trachyte-breccia, and in 
stalactitic forms in cavities. Attached to the specimen is some 
of the wall rock, which is too much altered for exact determination. 
It was, however, either an andesite or a trachyte, probably the latter. 
‘307. Gold quartz from the Pinares mine.” 
*¢308. [FE 1091.] Quartzose schist, wall rock in the Volcanes 
mine.”’ 
This proves to be light grey trachyte, kaolinized, and slightly 
impregnated with pyrrhotite. 
‘309. Quartzose schist, wall rock in the Volcanes mine.” 
The rock called quartzose schist in this district corresponds 
toatrachyte. (See No. 308.) 
«311. Ore from the Tolda Fria mine, showing the thickness 
of the rich vein. 
‘©3712. Ore from the Tolda Fria mine, showing the thickness 
of the rich vein. 
The Tolda Fria mine is in the Department of Cauca, about 
ten miles (three leagues) from Manizales. 
“313. [E 1092.|] Ore showing the thickness of the. rich vein 
at the Tolda Fria mine, near Manizales.” 
This is a section across a quartz vein, varying from one-half 
to one inch in width, and enclosed in a black talcose selvage. The 
ores consist of small pyrite crystals, sparingly distributed along 
the comb of quartz. 
