MINERAL REPOSITORIES. . Sometimes newer veins do not even run pa-. ,rallel with the older, but fairly terminate in them ; and this takes place ufually on the hang ing or upper fide. 9. In the fame veins, we fometimes meet with {wo or three different formations. Thus, in fome Saxon metalliferous veins, we find the lowed formation to be lead-glance ; immediately above it, a formation of native iilver; and the upper- mod fparry-irondone. In France, there are veins, whofe lowed formation is copper-ores ; immedi ately above it, a formation of iilver-ore; and the uppennod is a formation of iron-ore. Many more examples of the fame kind might be mentioned. 10. Great veins ufually run parallel with the general direftion of great valleys ; and this was to be expe&ed if veins have been formerly open fif- fures, and thefe fiffures formed by the linking of the unfupported fide of the mountain. II. Veins from the oldeft granite to the neweft alluvial depofite, Ihews that veins are compofed either of the finer fubftance of the rock in which they are contained, as is the cafe with thofe veins denominated Cotempor.ineous, or of fub- ftances more or lefs different from the rock, and which are frequently conne&ed with mountain-maffes or beds, that lie over thofe rocks by which thefe veins are travelled. Thus, no veins of granite are ever obferved {hooting from the oldeft granite formation into the fuperincumbent gneifs •, but veins of gneifs travcrfe this granite. No veins of mica-flate ever travede clay-flate, but veins of clay flate traverfe mica-fl ate.