MILLEB, ^NOBTHEKJf HIGHLANDS. 579 



looked upon as provisional and problematical ; and when I visited 

 that country in 1841, I looked anxiously for fossils, particularly in 

 the Duirness limestone, but without success. Nothing new was 

 heard of the geology of the district until Hugh Miller paid it a visit 

 in 1851, and read a memoir in the winter of that year before the 

 Royal Ph^'sical Society of Edinburgh, in which he endeavoured to 

 show that the conglomerate of Cape Wrath was the base, and the 

 quartzites and limestones of Duirness and Erriboll were the middle 

 and upper beds of the Devonian system, corresponding to the same 

 arrangement of the Old Red Sandstone rocks of Caithness. But 

 still no fossils were discovered until, in the end of 1854, Mr. Peach, 

 of Wick, happening to be in Duirness, observed a weathered fossil 

 in a dyke on the road-side ; this was enough for his penetrating eye ; 

 he immediately set to work ; and the result has been, as you all 

 know, the discovery of a complete fauna of Lower Silurian fossils in 

 the Duirness limestone. You are also aware that, with his accustomed 

 energy. Sir Roderick Murchison lost no time in revisiting Sutherland, 

 the scene of his former labours, in company with Professor ISTicol, of 

 Aberdeen ; that Professor Nicol laid before the Society a memoir con- 

 taining his opinion that the rocks in question would most likely 

 prove to be the representatives of the Carboniferous system of the 

 south of Scotland ; and you are also aware that Sir Roderick Mur- 

 chison has laid before this Society and the British Association for 

 the Advancement of Science several memoirs containing his present 

 opinions on the relations of the rocks in this district; — that the 

 gneiss of Cape "Wrath is the oldest rock in Scotland ; that the purple 

 sandstones of Cape Wrath are the next in the ascending order and 

 represent the Cambrian rocks ; and, proceeding eastward, that they 

 are succeeded in the ascending order by the quartz-rocks with 

 their associated limestones of Duirness and Erriboll, containing un- 

 doubted Lower Silurian fossils in the Duii^ness beds, and therefore 

 proving that the quartzites and limestones represent the Lower Silu- 

 rian formation ; and lastly, that the great central deposit of gneiss, 

 extending in this locality from the eastern side of Loch Erriboll to 

 the Bay of Strathy, would be found to dip under, or be overlaid by, 

 the Devonian or Old Red Sandstone of the north-east coast of Scot- 

 land along the line of junction between the gneiss and the Devonian 

 rocks from Strathy Bay southwards. 



Even after the discoveries of Mr. Peach, and since Sir Roderick 

 Murchison pubKshed the opiuions above stated, I still clung to the 

 hypothesis that, although Silurian rocks undoubtedly existed in the 

 north-west corner of Sutherland, sandstones and conglomerates of 

 true Devonian age would also be found in the same locality, and, to 

 satisfy myself on this point, I revisited the district in question in 

 August last, and the result of my researches and observations has 

 been to convince me that Sir Roderick Murchison is not only quite 

 correct in his facts and deductions, but even in his prospective 

 remarks regarding the progress of futiu'e discovery in this region, 

 and that his last memoirs on the subject are only an additional 

 proof of his astonishing sagacity in predicating from premises so 

 slender such clear and comprehensive, and, as the result has 



