_Translation._--Don Ferdinand VI. being King of Spain, and the Field Marshal Don Alonzo Fernando Hereda being Governor and Captain General of this place, St. Augustine, of Florida, and its Province. This fort was finished in the year 1756. The works were directed by the Captain Engineer, Don Pedro de Brazos y Garay. Every year hundreds of visitors rush into Fort Marion, and then the dungeon, with an awe-stricken feeling, as though the imaginary groans which are said to have been uttered here centuries since were ready to burst through the rocks and echo again, like the words of Plato, which his friends said froze in the winter, but on the return of spring thawed out again. Several years after the cession of Florida to the United States the north-east bastion of this fortress caved in, immediately under the highest tower, disclosing a dungeon fourteen feet square. On the same day was made the discovery of a square rock, cemented in an opening similar to those in the casemates, only much less, which was undoubtedly the entrance. A tempest there you scarce could hear, So massive were the walls. Some human bones and hair were then discovered and seen by volunteers from the ship Dolphin--a published account of which was forwarded to Washington, and deposited in the Congressional Library. The Smithsonian Institute has no knowledge of these cages, bones, or any thing pertaining to them ever having been placed there--which forever silences all inquiries in that direction. They told us, while in Washington, that when visitors came to the Institute asking information about them, the Professors were at a loss to know what they implied by their interrogations. It has long been a demonstrated fact that some of the St. Augustine natives have a way of answering questions asked about them in accordance with their impressions, regardless of dates or historic records. The following description of the old fort mysteries is a change from the iron cages--the writer having visited the dungeon before the cage tale had been invented: "We were taken into the ancient prisons of the fort-dungeons, one of which was dimly lighted by a grated window, the other entirely without light, and by the flame of a torch we were shown the half-obliterated inscriptions scratched on the walls long ago by prisoners. But in another corner of the fort we were taken to look at the secret cells which were discovered a few years since in consequence of the sinking of the earth over a narrow apartment between them. These cells are deep under ground, vaulted over head, and without windows. In one of them a wooden machine was found, which some supposed might have been a rack, and in the other a quantity of human bones. The doors of these cells had been walled up, and concealed with stucco, before the fort passed into the hands of the Americans."