———— 

Mar. 1899. THE OreEsS or CoLomBiA—NICHOLS. 165 
*¢358. Concentrates, different sizes.”’ 
‘360. Gneiss from near the Frias mine.’’ 
‘¢361. Limestone from near the Frias mine.’’ 
‘*361-1-20. ‘Twenty specimens of native silver and argentite.’ 
b] 
GOLD MINING DISTRICT OF LIBANO. 
The town of Libano, about fourteen leagues (forty-two miles) 
southwest of Honda and eight leagues (twenty-four miles) west of 
Ambalema, lies at an elevation of 3,500 feet. The mines are about 
three leagues (nine miles) south of the town. There are two depos- 
its, the La Plata veins and the Esperanza veins. Each consists of a 
group of quartz veins in mica schist, all approximately parallel and 
with a northwesterly strike. There have been a number of shafts 
sunk on different veins of the series.* 
The wall rock as shown in the collection is the ‘‘negro-negro’’ 
black schist instead of the mica schist mentioned by Mr. Pierce. 
The ores are blende with galena, pyrite and some chalcopyrite 
which at the outcrops carry silver and in depth gold. 
From the Libano district Sefior Gamba collected the following 
seven specimens, representing one mine: 
‘362. Black schist called ‘negro-negro,’ wall rock of La Plata 
del Libano mine.” . 
‘¢ 363. Pyrite and blende, ore from La Plata de] Libano mine.”’ 
‘364. Quartz, ore from La Plata del Libano mine.” 
‘¢ 366. Ordinary quartzose ore from La Plata del Libano mine.” 
‘367. Ordinary quartzose ore from La Plata del Libano mine.”’ 
“©368. [E 1130.] Ordinary quartzose ore from La Plata del 
Libano mine.’’ 
The quartz contains pyrite, galena and blende. 
THE CHINA RIVER GOLD AND SILVER MINING DISTRICT. 
The China river is not to be found on any of the maps which 
were consulted. From Restrepo’s account, in which the deposit is 
briefly described as a ‘‘ silver vein,” it seems to be not far from the 
city of Ibague. According to the catalogue the ore is galena, pyrite 
and blende in quartz, The wall rock appears to be chlorite schist, 
*Wm, Pierce, Tr. A. I. M. E., Vol. XVI., p. 301, 1889. 
