146 FirLp CoLtuMBIAN MuseEuM—GEOoLOoGY, VOL. 1. 
chloritic schist (like No. 133) and an altered trachyte heavily impreg- 
nated with pyrite, chalcopyrite, galena and blende, with some strongly 
magnetic pyrrhotite. Aragonite occurs in minute incrustations. 
(755. [E 1197.] Ordinary quartzose ore from the Zancudo 
mine.” ) 
Dark-colored quartz impregnated with sulphides, like those of 
No. 154, and with many angular fragments of the light-colored altered 
trachyte, which are penetrated everywhere by numerous small quartz 
veins. The formation does not appear to be that of a brecciated 
vein, but rather to have originated by metasomatosis of the trachyte. 
‘756. Ordinary quartzose ore from the Zancudo mine.”’ 
‘©7157. [E 1069.] Pyrites and blende, schetderz from the Zan- 
cudo mine.” ; 
Scheiders is defined as an ore which has been separated from the 
poor ore and gangue by picking over by hand. 
In this specimen, pyrite, blende and galena coat and impregnate 
colorless granular quartz. 
‘¢158, Molino ore from the Rosario mine.” 
‘‘~59. [E 1070.] Molino ore from the Rosario mine.’’ 
Here blende, pyrite, galena and quartz replace a trachyte brec- 
cia. The specimen contains some unaltered trachyte and some com- 
pact quartz and sulphide in which the breccia is not visible. 
‘¢160. Molino ore from the Rosario level, Zancudo mine.” 
‘161, Veinstuff, feldspathic clay from the wall rock of the 
vein, ”’ 
‘‘162. [E 1207.] Pyrite’ and blende, schezderz from the Zan- 
cudo mine.” | 
©1763. Schetderz with galena.”’ | 
‘164, Ordinary quartzose ore from the Rosario level, Zancudo 
mine.” 
‘¢165. Galena, ore from the Zancudo mine.” 
‘©1766. Ordinary quartzose ore from the Paz level, Zancudo 
mine.” 
‘‘167. Ordinary quartzose ore from the Paz level, Zancudo 
mine.” | 
“168. Quartzose molino ore from the Paz level, Zancudo 
mines” 
‘““(E 1071.] Quartzose scheiderz from the Paz level, Zancudo 
mine.’”’ 
This is a mixture of chalcopyrite, blende and galena which thor- 
oughly impregnates a light, granular quartz. 
‘‘170.. [E 1634.]. Pyrite and blende, schederz from ptheo eas 
level of the Zancudo mine.”’ 


