108 PROCEEDINGS OF TEE GEOLOGICAL SOCIETY. [Jan. 8, 



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 pas- 

 sage 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 pa- 

 laeontological 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 patcbes of Secondary rocks 

 which occur in Scotland, with a view to show how far tbe history 

 of tbe Mesozoic periods witbin 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 exami- 

 nation of the Theoretical Questions suggested by a study of their 

 physical characters and relations, and of the peculiarities of their 

 faunas. 



Part I. — Strata oe 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 Eev. J. M. Joass. This charter is 

 quoted in the ' Origines Parocbiales Scotise ' (vol. ii. pt. ii. p. 727). 



The earliest account of the working of the coal is contained in Sir 

 Eobert Gordon's quaint old work ' Genealogy of the Earls of Suther- 

 land,' 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, iu 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. 



