Prof. C. Lcqmorth — Close of the Highland Controversy. 101 



14. By the agency of this lateral earth-thrust, the Archaean, the 

 plutonic, and included patches of sedimentary rocks have been 

 locally sheared and flattened out into rocks resembling halle- 

 fliutas ' and rhyolites, even finely -laminated shales. 



15. This Eastern Metamorphic Series of Sutherland and Koss not 

 only contains Archaean rocks, but also local patches of meta- 

 morphosed Paleeozoic,^ intrusive, and segregatory rocks, 

 together with local patches of material pi'obably compounded 

 of all these in different degrees.^ 



16. This Eastern Metamorphic Series has received its present strike, 

 pseudo-bedding and its present foliated and mineralogical 

 characteristics through the agency of the crust movements 

 which have operated within the district since Lower Silurian 

 times, '^ 



Some of these conclusions may appear startling at first sight to 

 those who have not followed with interest and appreciation the more 

 recent developments of our knowledge of the geological phenomena 

 of mountain districts. But they agree precisely with the results 

 which have been already worked out by extra-British investigators. 

 The stratigraphy of the North-West Highlands, as I have more than 

 once suggested, is precisely of the same character as that so admirably 

 described and illustrated by Heim = in his magnificent work upon the 

 Alps of Central Switzerland. The metamorphic phenomena of the 

 north-west, too, are identical with those so minutely detailed and 

 photographed in Lehmann's most valuable work on the meta- 

 morphic rocks of the Saxon ^ Erzgebirge. Continental geologists, 

 British amateurs, and the ofiScers of the Geological Survey are now 

 at one and the same point. They stand together on the shore of a 

 new world of geological discovery, full of the richest promise. 



But it must not be forgotten that the results already attained in the 

 north-west are merelj^ the preliminary sketches for a great and a 

 most necessary work, namely, the detection of the chief laws of 

 mountain stratigraphy and the discovery of the more important 

 processes of regional metamorphism. Investigators are certain to 

 crowd in hosts to the new ground in search of fresh discoveries, and 

 geological pamphlets upon the district will soon be thick as leaves 

 in Vallambrosa. All this will advance the science greatly, and much 

 good will come of it. But before we can advance far beyond our 

 present standpoint, it is absolutely requisite that the debatable region 

 shall be accurately mapped and its complicated stratigraphy un- 

 ravelled. This is a work which can only be accomplished speedily 

 and in its entirety by the Geological Survey. And it is a preliminary 

 and necessary work of the very first importance, for upon its speedy 

 and satisfactory completion hang some of the most vital problems in 

 •British stratigraphical as well as in general theoi-etical geology. 



. 1 Lapworth, loc. cit. 1884. 2 Compare Hicks, 1883, Q.J.G.S. p. 147. 



3 ],apworth, 1884, ibid. p. 104. * Lapworth, 1884, ibid. p. 105, 



* Heim, Mechaimmus der Gebirgsbildimg, Basel, 1878. 

 ^ Lehmami, Entstehung der AltkrystaLliuischm Schiefergesteine, Bonn, 1884. 



