By J. MacCulloch, M.D. Chemist to the Ordnance, and Lecturer on Chemistry at the Royal Military Academy at Woolwich.
I Have the honor of presenting to the Society three drawings which I have selected from my portfolio, for the purpose of illustrating the changes which the influence of time and weather produces on certain varieties of granite. The subjects are all chosen among the granites of the west of England; and that I might at the same time preserve memorials of circumstances which are remarkable independently of their geological interest, I have taken two of my examples from places which have called forth more admiration from the common spectator than even from the philosopher, and which form two points of attraction for the curious or idle who annually visit Cornwall. Not only indeed have idle curiosity and ignorant speculation busied themselves in accounting for phenomena which many of the vulgar have deemed little less than miraculous, but learned antiquaries have tortured their inventions and have constructed religious systems for the purpose of explaining these very simple and intelligible natural appearances; by the rites of a mysterious and Druidical worship. I trust I shall be pardoned, if while I deduce from these facts the geological consequences which depend on them, I likewise give a more particular detail of the appearances themselves which have excited so much of the attention of all visitors.