Geol. Mag. 1920. 



Plate VIII. 



Fig. 1.- — The great diamond mine at Sopa, near Diamantina, Minas Geraes, 

 Brazil. Note the excavation in the soft sericitic schist. The surrounding 

 country is hard quartzite. 



Fig. 2. — The great diamond mine at iJoa \'ifeta, near Diamantina, Minas Geraes, 

 Brazil. Note the fissure-like excavaticn of the mhie. The surrounding 

 plateau is formed of hard quartzites. 



To face p. Ur.} 



