Sir,—The Geological Magazine for August, p. 394, contains a report of a paper communicated by the Rev. J. M. Mello to the Geological Society, on the 22nd June, 1870, on the above subject. On the 7th September, 1869, I had the honour to read a paper on the same subject to the Natural Science Section of the Nottingham Literary and Philosophical Society. Hence I beg to claim priority in publication on behalf of the above Society. Apart from this, I, of course, do not complain that Mr. Mello should happen to select a very interesting section like that in Tideswell Dale, no doubt being quite unaware that I had already published an account of the same. The sole, though rather dubious, deduction that the author is reported to have made, is “that the columnar clay-bed may perhaps be a local development of that which forms partings in the limestone near Litton Tunnel.”