It was with great interest that I read in the Geological Magazine Vol. X. for June, 1873, the Rev. O. Fisher's able paper on the Formation of Mountains; and although I cannot altogether agree to his reasoning, I have to thank him for re-calculating, more correctly no doubt than I have done, my table of the altitude of domes, and also for explaining several points which I had not clearly conceived before. Nevertheless, I think that I shall be able to show that his arguments against the theory that I have advocated are not well founded.