The earthquakes of 1812, which were so disastrous in South America, are known to have propagated themselves towards the north, and they exerted some striking effects in the lower part of the valley of the Mississippi, sending down into the channel of the latter, large areas of deluvial earth, as was instanced, in a remarkable manner, at New Madrid. Portions of the forest, back of this town, sunk, and gave place to lakes and lagoons. These effects were also witnessed, though in a milder form, in the more solid formations of the mine country. Soon after reaching Potosi, I visited the Mineral Fork, a tributary of the Merrimack, where some of these effects had been witnessed. I descended into the pit and crevices of the Old Mines. These mines were explored in the metalliferous rock. Every thing had an old and ruinous look, for they had been abandoned. Large quantities of the ore had been formerly raised at this mine, which was pursued into a deep fissure of the limestone rock. I descended into this fissure, and found among the rubbish and vein stones, large elongated and orbicular masses of calc spar, the outer surfaces of which bore strong marks of geological abrasion. They broke into rhombs very transparent, and of a honey-yellow colour. Mr. Elliot, the intelligent proprietor of this mine, represented the indications of ore to have been flattering, although every thing was now at a stand. Masses of sulphuret of zinc, in the form of blende, were noticed at this locality. Mr. Elliot invited me to dine, and he filled up the time with interesting local reminiscences. He stated, among other facts, that a copious spring, at these mines, dried up during the remarkable earthquakes of 1812. These earthquakes appear to have discharged their shocks in the direction of the stratification from the southwest to the northeast, but they spent their force west of the Mississippi. Their chief violence was at Natchitoches and New Madrid, at the latter of which they destroyed an immense area of alluvial land. Their effects in the Ohio valley, lying exactly in the direction of their action, were slight. A Mr. Watkins, of Cincinnati, accompanied me on this examination, and rode back with me to Potosi.