Sa 
Mar. 1899. THe Ores or CoLtompia—NICHOLS. 143 
This specimen, which is not in the collection, was probably 
another chlorite schist. 
‘735. Limestone from the Quiuna mine.” 
‘736. Limestone from the Quiuna mine.”’ 
Besides the limestone country rock of the Quiuna mine, calcite 
occurs among the gangue minerals of the Frontino mine, and is the 
major part of the gangue mineral proper in the famous Espiritu Santo 
mine, on the Isthmus of Darien, where the ore occurs with calcite 
in small pockets (amygdu/es?) in one of the more acidic lavas.* 
‘737. Quartz from the Quiuna mine.”’ 
‘©7138. Quartz and limestone from the Quiuna mine.”’ 
‘739. Quartz and limestone from the Quiuna mine.” 
‘‘t40o. Quartz and limestone from the Quiuna mine.” 
IRON MINING DISTRICT OF AMAGA. 
Amaga, a town of 6,400 inhabitants, upon the Central Cordillera, 
situated on the east side of the Cauca Valley, about twenty miles 
southwest of Medellin, is the seat of the Colombian iron mining 
and smelting industry. Formerly gold mines were worked there, 
but none are listed by Sefior Gamba as being in operation at the 
present time. According to his catalogue, the country rock of the 
region is sandstone, associated with porphyry. 
A number of deposits of coal are given in’Reclus’ map of the 
region. The iron ores, judging from the Museum specimens, are 
light brownish-yellow, shaly siderites. They are smelted at Amaga, 
From Amaga Senor Gamba collected the following eight spe- 
cimens: 
‘‘r4r. Sandstone.” 
taza, Fk orphyry.”’ 
oe 41 t. FrQO.| Lron stone.” 
An impure shaly siderite. 
144.7 ifon stone.” 
Matas) LON Stone.’ 
‘746. White iron from the Amaga furnaces.”’ 
‘‘t47. Gray irons from the Amaga furnaces.” 
‘148. Quartzite from the road between Amaga and Zancudo.”’ 

***The Darien Gold Mining Region of Colombia’’: E. J. Chibas, Eng. Mag., Vol. XVI., 
p. 49. 1898. 
