Ancient ore-reduction works, _arrastres_, canals, ditches, excavations, tunnels, pits, ruined buildings, and in some cases falling church walls, all of this bygone age, are encountered throughout the country, scattered far and wide. Those who lived and moved and had their being therein lie mingled with the dust these centuries past, and kind nature has often covered up the evidences of their handiwork with flower and foliage. There was a steady flow of the two precious metals to the City of Mexico from the innumerable mines of the regions which produced them. To attempt to describe these mines, even those renowned for their richness, would fill a chapter alone. Fantastic displays of wealth are recorded by the owners of some of the great silver-producing mines--the bridal chambers of a palace, lined by the father of a bride with silver bars; the footpath from the _plaza_ to the church paved with great silver ingots, for the bridal party. A famous hill of iron--standing on the plains of Durango, stands out also from the historical vista of metallurgical discovery of those early days. In 1552 Vasquez de Mercado, a Spaniard of wealth and family in Mexico, living in Guadalajara, heard from the Indians that a great mountain of pure silver existed on the boundless plateau far to the north. Arming an expedition he set forth with this vain illusion actuating him, and travelled on day after day expecting that every sunrise would gleam upon the burnished slopes of this silver mountain. Battles were fought with the savage Indians who inhabited the plains, but vanquishing these the deluded party pushed on. At last, on the horizon, the hill rose; they approached it: it was iron! Sleeping sore-hearted at its base that night, Mercado and his companions were attacked by Indians, various soldiers killed, and he himself wounded. Returning homeward towards Guadalajara, the unfortunate leader succumbed to his wounds, fatigue, and the ridicule of his companions, and he perished. But the great Cerro de Mercado, the hill of iron, still remains one of the wonders of Mexico.