Geological sketches, at home and abroad . andstone was not continuously deposited, ormore probably because it was unequally worn down beforethe next group was accumulated upon it. Evidently thesolution of this question has an important bearing on anyreconstruction of the early geography of the region. Above the red sandstones and creeping transgressivelyacross them lies the deep pile of white quartzites, lime-stones, and schists, which Mr. C. W. Peachs discovery ofrecognisable fossils in them at Durness showed to be otLower Silurian age. Another well-marked contrast of sceneryis presented wher
Geological sketches, at home and abroad . andstone was not continuously deposited, ormore probably because it was unequally worn down beforethe next group was accumulated upon it. Evidently thesolution of this question has an important bearing on anyreconstruction of the early geography of the region. Above the red sandstones and creeping transgressivelyacross them lies the deep pile of white quartzites, lime-stones, and schists, which Mr. C. W. Peachs discovery ofrecognisable fossils in them at Durness showed to be otLower Silurian age. Another well-marked contrast of sceneryis presented where these rocks abut upon those just de-scribed. The quartzites rise into long lines of bare whitehills which, as the rock breaks up under the influence ofthe weather, are apt to be buried under their own debriseven up to the summits. Here and there outlying patchesof the white rock may be seen gleaming along the crests ofthe dark sandstone mountains, like fields of snow or nascentglaciers (Fig. 19). Quartzites, limestones, and schists dip. 150 GEOLOGICAL SKETCHES. [vn away to the east and pass under the vast series of youngerschists which form most of the rest of the Scottish High-lands. This order of succession, first established byMurchison, can be demonstrated by innumerable lines ofnatural section. I have myself traced it through themountainous country from Cape Wrath to Skye, and inmany traverses across Sutherland and Ross. I have soughtfor evidence of the reappearance of the old or fundamentalgneiss of the north-west, and have ransacked every Highlandcounty in the search, but have never found the least traceof that rock beyond its limits in Sutherland and Ross. Itsdistinctive gneisses and other crystalline masses, so wonder-fully unlike anything else in the Highlands, never reappearto the east. And that strange mammillated, bossy surfaceis found in the north-west alone. To realise what the appearance of the old gneiss at thepresent surface involves we must bear in mind tha
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectgeology, bookyear1882
