_Llandudno, on the Great Orme's Head._--Having occasion to visit the above interesting place last summer, among other objects of curiosity, I was induced to visit a "cavern," which the inhabitants said had been lately discovered, and which they said had been used by the "Romans" (Roman Catholics) as a place of worship. A party of five hired a boat for the purpose of visiting the place, which is about two miles from the little bay of Llandudno; for it is quite inaccessible by land. We arrived in about an hour; and were quite surprised at the appearance of the "cavern," which seems to have been made as private as possible, and as inaccessible, by large stones being piled _carelessly_ upon each other, so as to hide the entrance, and which we could not have found without the assistance of the sailors. The "cavern" is about ten feet high, lined with smooth and well-jointed stone work, with a plain but nicely executed cornice at the height of seven or eight feet. The shape is heptagonal, and the fronts on each side are faced with smooth stone; the space from front to back, and from side to side, is equal, about six feet six inches. On the right, close to the entrance, is a font, sixteen inches across inside, twenty-two outside, and eight or nine inches deep. There is a seat round, except at the entrance; and there has been a stone table or altar in the centre, but a small portion of it and the pillar only remain. The floor has been flagged, but it is in a very dilapidated state. That it was used for worship, there is little doubt; but how and when it was fitted up, seems marvellous. It is not mentioned by Pennant, or any Welsh tourist. Will any of your correspondents oblige me and the public with the history of this "cavern," as it is called, at Llandudno? L. G. T. _Johnson's House, Bolt Court._--Can any of your readers inform me whether the house in which Dr. Johnson resided, and in which he died, situate in Bolt Court, Fleet Street, is yet in existence? You are probably aware that an engraving of it appeared in the _Graphic Illustrations_ edited by Mr. Croker, and prefixed to this engraving was an announcement that it was destroyed by fire. There is reason, however, to believe that this is a mistake, and that the house so destroyed by fire belonged not to Johnson, but to Johnson's friend, Allen the printer.