CHAPTER 6.. Configuration of the Ground At Santo Domingo.--Excavation of

Configuration of the ground at Santo Domingo.--Excavation of valleys.--Geology of the district.--Decomposition of the rocks. --Gold-mining.--Auriferous quartz veins.--Mode of occurrence of the gold.--Lodes richer next the surface than at lower depths. --Excavation and reduction of the ore.--Extraction of the gold.-- "Mantos".--Origin of mineral veins: their connection with intrusions of Plutonic rocks.