260 



J. H. COLLIN'S OZI^" THE GEOLOGY 



Figs. 3-8. — Cross-sections of the South Lode at Bio Tinto, showing 

 profiles of the ground removed. (Scale, 1 to 7500.) Pig. 3. Sec- 

 tion at San-Inocente Shaft. Figs, 4-8, respectively 150, 200, 300, 

 350 metres to the East. 



Fig. 3. 



Fi-. 4. 



FiR. 5 



Fi2:. 6. 



Porphyry. 



Slate. 



Pyrites. 



p^^p^ Porphyry worked 

 ■-"•---—■' away. 



Slate worted 

 away. 



Permginoxis breccia, and gozzan. 



Pyntes worked 

 a.way. 



the neiglibonrliood of Eio Tinto ; but at present none of them are 

 being worked, although a great many of them were in active 

 operation some ten j^ears since. The slate in the neighbourhood is 

 generally of a purplish colour; sometimes it contains a series of 

 concretionary kernels or " eyes " of cobaltiferous oxide of man- 

 ganese, as shown in the sketch (fig. 9), which is taken from a 

 specimen occurring a little to the west of Bella Yista. 



In the pyrites-region mineral veins other than those of cupreous 

 pyrites and of manganese are extremely rare and of comparatively 

 little importance. A few veins of lead, copper (oxides, sulphides, 

 and carbonates), of blende, and of other minerals are known to 



