Copper-Tin Veins of the Akéuobé District. 49 



ores containing a small quantity of cassiterite are extracted from 

 some working parts of the vein, while high-grade tin ores con- 

 taining more or less chalcopyrite are also being mined at other 

 places of the same vein. 



(4) The Deposition of Zincblende. 



Occasionally veinlets of zincblende with a width varying from 

 a few millimeters to several centimeters are found in the composite 

 vein. They cut through massive chalcopyrite ores, often passing 

 into ramifying stringers. The veinlet consists mainly of granular 

 massive zincblende admixed with varying amounts of quartz. Very 

 small quantities of galena, chalcopyrite and secoiidary bornite in 

 minute specks are associated v-ith it. 



The product of this stage must be distinguished from similar 

 ones of the earlier stages, because zincblende was deposited to a 

 less extent, as already stated, in the first stage of mineralization 

 in association with the cassiterite- bearing ring-oi-e, and in others. 



(5) The Deposition of Barren Quartz. 



Veins and veinlets of quartz representing the last mineralization 

 are found everywhere in the veins of the Akénobé district. They 

 vary in thickness from a few millimeters to several decimeters and 

 cut the products of all earlier stages, filling the reopened fissm'es 

 in the composite veins, and either running parallel to the selvages 

 or irregularly across them (Fig. 9). They consist of massive, 

 milky or transparent quartz, and are rich in drusy cavities lined 

 with slender crystals of quartz. A very small quantity of chal- 

 copyrite in the form of small masses and specks occurs sporadically 

 in the veins imder consideration ; it belongs to the same stage 

 of mineralization as the associated quartz. Considered from an 



