natural history, geology, and archaeology of the county from which he derives his title, and of which he is almost the sole proprietor. His Grace the Duke of Sutherland has conferred a great benefit on science ; and the same nobleman has placed myself under deep personal obligations by allowing me the freest access to the various documents and plans which could in any way aid me in carrying on my studies. The kind solicitude in my behalf of His Grace's Factor, Joseph Peacock, of Rhives, demands my warmest acknowledgments. To very many local collectors and observers I am indebted for the opportunity of studying their specimens, and for the communication of valuable facts. Among these I especially desire to render my warmest thanks to Mr. Grant, of Lossiemouth, the Rev. J. Morrison, of Urquhart, Mr. Martin, of Elgin, Mr. Edward, of Banff, Professor Nicol, of Aberdeen, Mr. Hugh Miller, junior, Miss C. Allardyce, of Cromarty, Mr. Fowler, of Golspie, and Mr. M'Corquodale, of Dunrobin.
But to two local geologists, whose names are well known to this Society, I am laid under still deeper obligations. To the Rev. J. M. Joass, of Golspie, and the Rev. Dr. Gordon, of Birnie, near Elgin, I am indebted for that constant assistance and ever-ready advice which they are so well qualified to give with regard to their respective districts, and which is so indispensable to and difficult of attainment by an investigator in a district which is new to him. The kind interest which they have taken in my labours, and their constant solicitude in seeking to bring useful materials to aid me in the difficult task which I had undertaken, lay me under a debt of gratitude which, though I can never discharge, I yet gladly take the present opportunity of acknowledging.
The orthography of all local names in the present memoir has been kindly determined for me by my friend Mr. Joass ; but in doing this he has, at my suggestion, consulted the convenience of geologists visiting the country, rather than the strict requirements of Gaelic scholarship.
In studying the series of fossils from the east of Scotland, many of which are new to science, I have to acknowledge the valuable assistance afforded to me by Mr. Carruthers, Dr. Lycett, Prof. P. M. Duncan, Sir Philip Egerton, Prof. T. Rupert Jones, and Mr. Davidson. The last-mentioned palaeontologist has kindly added a note to this paper on some species of Brachiopoda of especial interest ; many other new forms will find a place in monographs, now in course of preparation, on the groups to which they belong ; the remainder will be described, in connexion with new species from the West Coast of Scotland, in a supplement to this memoir. In these palaeontological studies, the assistance of Mr. Etheridge's great experience, always most liberally rendered to me, has been invaluable.
II. Physical Relations of the Secondary Rocks on the East Coast of Scotland.
The Secondary rocks which arc known to occur in situ on the
