In the immediate neighbourhood of the castle, and, indeed, running under the southern edge of its _enceinte_, are the celebrated caverns which have recently been explored, and for the first time correctly planned by Capt. James, whose excellent account of them is well known. These caverns are excavated in the chalk, which forms a cliff south of the town, and from the base of which they are entered. The chalk here dips northerly, at about ten degrees, and the hardest bed and the most suitable for building purposes lies at the base of the cliff and is about 6 or 7 feet thick. This bed has been largely quarried by open “patching” in the broken ground south of the cliff, which, indeed, is apparently artificial, and produced by these excavations, and it was only when the bed became too deep for that mode of working that the quarrymen had recourse to mining operations. These later works are, in general plan, composed of a gallery parallel to, and a few feet within, the face of the cliff, from which, at a right angle, eight parallel stalls are carried north-eastwards. The extreme points of the excavation are a little over 55 yards north-west and south-east, by 32 yards north-east and south-west; but the area actually excavated is only about 1,150 yards, and the cubical contents about 2,330 yards. The plan alone would show that they were opened for quarries. But, besides this, although much solid chalk has been removed, the excavation is nearly choked up with the immense quantity of “small” produced by unskilful working, and through which narrow paths are left to get at the face of the work. It is evident that this is not _débris_ brought in, nor caused by the fall of the roof, which is remarkably sound. It is simply broken chalk which has been thrown back as the miners proceeded, and remains undisturbed. The character and presence of this rubbish not only shows that the excavation was a quarry, but that it never was used for anything else, neither as a granary, nor a cellar, nor for human habitation, for nowhere has it been cleared away so as to set any part of the cavities free for such purposes. Nearly in the deepest part of the working, about 60 feet below the surface, the caverns have been pierced by a well, sunk, it is said, in the garden of the governor of the old gaol. This well has been carried through the caverns, if to water, probably to a depth of another hundred feet, but it has subsequently been covered over with plank, at the level of the cavern floor, and so now remains. The pipe of the well above is very rugged, as though sunk by unskilled workmen—perhaps convicts,—and is stained, as though used as a cesspool. Also, for many yards around, the rubbish, elsewhere of pure white, is dark and foul, as though, failing to reach water, or afterwards disused for that purpose, the well had been employed as a receptacle for all the filth of the prison.