Triassic age, and must once have formed the natural base of those Liassic and Oolitic deposits of the north-east of Scotland which I described forty years ago " *.
Most strikingly has the anticipation contained in the above passage been verified by my researches among the newer strata of Sutherland during the past year. I have been able to detect there the formation so long the subject of controversy, and to show that its relations to overlying rocks are exhibited in a section free from tbose sources of difficulty and doubt which have so long baffled geologists in Elginshire. In Sutherland the rocks in question are seen to be covered conformably by a great series of strata which, as will be seen from their large and distinctive faunas, represent various members of the Middle and Lower Lias. Thus, as in so many similar instances, the apparent discrepancy between the palaeontological and stratigraphical evidence is dissipated by further inquiry, and the proof of the Triassic age of the beds in question is rendered complete.
The object of the present memoir is to give the results of a careful study of the small but highly interesting patches of Secondary rocks which occur in Scotland, with a view to show how far the history of tbe Mesozoic periods within that area can be reconstructed from them. It is proposed to divide the subject into three parts, which will be successively communicated to this Society, the first being embodied in the present paper. The three divisions of the memoir are as follows : —
I. The Secondary Strata of the Eastern Coast of Scotland.
II. The Secondary Strata of the Western Coast and Islands of Scotland.
III. A general Comparison of the Scottish Mesozoic Strata with their equivalents in England and on the Continent, and an examination of the Theoretical Questions suggested by a study of their physical characters and relations, and of the peculiarities of their faunas.
Part I. — Strata of the Eastern Coast.
I. History of Previous Opinion.
The coal-beds of Brora were certainly kuown as early as the Year 1529, as is proved by an ancient Sutherland charter, which was brought under my notice by the Rev. J. M. Joass. This charter is quoted in the ' Origines Parochiales Scotise ' (vol. ii. pt. ii. p. 727). The earliest account of the working of the coal is contained in Sir Robert Gordon's quaint old work ' Genealogy of the Earls of Sutherland,' written in 1630.
John Williams, the author of the ' Natural History of the Mineral Kingdom,' was lessee of the Inverbrora Colliery from 1764 to 1769. He does not, however, in his work, which was published in 1810, record any of his observations and experiences in Sutherland, though he notices the peculiar characters and gives some details
- Siluria, 4th edition (1867), p. 267.
