Frof. C. Lapicorth — Close of the Highland Controversy. 99 



out the details of the subject. Should there be, however, any stray 

 geologists who still hesitate to accept the statements of Messrs. 

 Peach and Home respecting the extraordinary nature of the strati- 

 graphical phenomena in our British mountain region, and fail to appre- 

 ciate the brilliant light thus thrown upon the true mode of origin of 

 some of the crystalline schists, it may aid them in arriving at a correct 

 opinion to note for themselves how two sets of investigators, coming 

 to the Durness-Eriboll district with theoretical views almost diametri- 

 cally opposed to each other, have independently arrived at, and 

 independently made known, the same general conclusions, as regards 

 (1) the sequence; (2) the extraordinary stratigraphical phenomena; 

 (3) the mode of metamorphism ; (4) its Post-Cambrian date. 



We are now for the first time in a position to take stock, as it 

 were, of the common acquisitions of all parties on the subjects of the 

 stratigraphy and metamorphism of the rocks of the North-West 

 Highlands. The more vital conclusions laid down in the Eeport of 

 Messrs. Peach and Home, or incidentally covered by it, are sum- 

 marized below. It will be apparent on testing the references given 

 (which include merely a single citation for the different investigators 

 in each case) that they are in thorough accord with similar conclusions 

 arrived at by one or by many of the opponents of the Murchisonian 

 hypothesis, a circumstance which affords a strong presumption of 

 their general correctness, and a high probability that they will soon 

 be accepted by all. 



Synopsis of our present ideas of the Geology of the Bocks of the 



North- West Highlands. 



(a) The Sequence. 



1. The unaltered PalEeozoic rocks of North-west Sutherland and 



lioss consist of four ^ main members — the Torridon Sandstone, 

 the Quartzite, the Fucoid Group, and the Durness Limestone. 



2. These major groups admit of subdivision into several recogniz- 



able zones,'^ capable of being easily identified upon the ground. 



3. The Durness-Eriboll Limestone is the newest sedimentary rock ^ 



in the district. 



4. The Upper Quartzite and Upper Limestone of Murchison are 



non-existent ; * the so-called Upper Quartzite is the Lower 

 Quartzite repeated, and the so-called Upper Limestone is in 

 reality a repetition of a part of the Durness Limestone itself. 

 lb) The Stratigraphy. 



5. There is no ^ conformable upward succession, as held by Murchi- 



son and his followers, from the Silurian Rocks into the Eastern 

 Gneissic series ; for — 



1 Nicol, Quart. Journ. Geol. Soc. 1856, p. 20, etc. Hicks, a.J.G-S. 1878, p. 813. 

 Callaway, Q.J.G.S. 1883, p. 358, etc. Lapworth, Geol. Mag. 1883, p. 123, etc. 



2 Lapworth, Geol. Mag. 1883, p. 126, etc. Callaway, Q.J.G.S. 1883, p. 358, etc. 



3 Nicol, Q.J.G.S. 1861, p. 88, etc. Callaway, Q.J.G.S. 1881, p. 244. Lap- 

 worth, Geol. Mag. 1883, p. 127. 



* Nicol, Q.J.G.S. 1861, p. 91, etc. Hudleston, Geol. Mag. 1882, p. 394. 

 Lapworth, Geol. Mag. 1883, p. 127. Callaway, Q.J.G.S. 1883, p. 367. 



6 Nicol, Q.J.G.S. 1861, p. 86. Hicks, ibid. 1883, p. 157. Callaway, Q.J.G.S. 

 1883, p. 357. Lapworth, Geol. Mag. 1883, p. 127. 



