*4* MINERAL REPOSITORIES. , t 14. All true veins appear to have been formerly open fiffures; and thefe fijfures feem to have been filled from above with the mineral fubftances they now contain *. Such is the theory of Werner. a. Thefe Allures may have been formed in differ ent jvays; as by the unequal accumulation of rocky matter, at the time of depofition; by the lofs of fupport, owing to the diminution of the water ; by the deficcaticm of ftrata, caufed by the confolidation of cryftalline depofitions; fometimes* by earthquakes, and the foftening of ftrata during long-continued rains. r b. 1 hat all veins have been formerly open fiffures, Is Ihewn by the perfedt agreement of veins and fiffures in their various charadters. Thus, veins agree perfedtly with fiffures in their fliape and pofition. Like them, they are feldom much con torted in their courfe ; they wedge out at their extremities, and diminilh in breadth towards their bottom ; and in many cafes even clofe completely; and they have frequently lateral branches on their hanging fide. c. Their inclination, like that of fiffures, is always more inclining to the perpendicular than the ho rizontal line ; and they generally dip in the di- redtion of the declivity of the mountain in which they are fituated ; and,* laftly, veins of the fame formation, like fiffures, have ufually the fame di- redtion. d. That * This does not, ftridtly fpeaking, include cotempora- neous veins, for reafons fufficiently obvious.