These ruins are both beneath and upon a natural hill of oval form measuring about two miles in circumference and from three hundred to four hundred feet in height, authorities differing considerably on this point. At the foot of the hill on its northern side, are the entrances of two tunnels, one of which extends to a point eighty-two feet from the edge of the hill, where it terminates abruptly. The second tunnel penetrates the solid limestone of the hill in the form of a square gallery nine and a half feet high and broad, extending inward for several hundred feet and branching into several auxiliary galleries, which terminate in some instances abruptly. The floors are paved with small blocks of stone, to a thickness of a foot and a half; masonry in some places support the sides, and all the interior surface shows traces of red paint upon the polished cement coating with which it was finished. The principal gallery, after turning a right angle toward the left and extending some hundred feet in a straight line, enlarges into a subterranean chamber eighty feet long by about sixty feet in width. Two circular columns of living rock were left in making the excavation as supports for the roof. The most singular feature connected with the chamber is the perfectly circular excavation found at its south-east angle, or that corner of the room diagonally opposite to the corner at which the passage-way enters it. This circular apartment is only about six feet in diameter, and while it is no deeper than the adjoining chamber, rises above its ceiling in a dome-shaped roof, lined with stones hewn in curved blocks. The curve of this dome-like ceiling corresponds with that of a well-proportioned Gothic arch. At the apex of the dome, a round hole ten inches in diameter extends vertically upwards; some suppose to the pyramid above, but a moment’s calculation suffices to show that in view of the considerable diameter of the hill and the comparatively short distance from the chamber to its exterior slope, such is impossible. The exterior of the hill presents a most wonderful display of masonry. Its entire circuit is compassed with five terraces of well-laid stone and mortar, faced with perpendicular walls. Each terrace of masonry is about seventy feet in height, and is constructed in an irregular line, forming sharp angles, like the bastions of a fortress; each wall supporting the terraces rises above the level of their respective platforms in parapets, evidently for defence. The pavements of the platforms are of stone and inclined slightly toward the south-west, with a view to draining off the rainfall. Dupaix is the only explorer who mentions the means of ascent, which he describes as a roadway eight feet wide, leading to the summit. The summit platform measures 285 by 328 feet, and is surrounded by a wall which is perpendicular on the inside, and on the outside conforms to the slope of the terrace wall of which it is an extension. This