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ON THE RED SANDSTONE, ETC.

peculiarly marked beds. But while I must regard the iden-tity of the Bed Sandstone of the north-eastern and north-western coasts of Scotland as by no means fully established,I am at least strongly of opinion that, as they are essentiallythe same in their aspect, order, and components, they repre-sent also the same period in the history of the globe. Fromfinding the strata of the Old Bed Sandstone upturned againstour primary mountains, and truncated atop, and from thosedetached fragments of the system which occur as insulatedhills far in the Highland interior, I was led to conclude,many years ago, that this deposit had at one time overlaid allthe primary rocks of Scotland , from the southern flanks ofthe Grampians to the northern boundary of Sutherland,—aconclusion to which Sir Charles Lyell , in the later editions ofhis “ Elements,” has approvingly referred, as coincident withviews on the subject entertained by himself. And these are-naceous rocks of Assynt, with their associated limestones andmarbles, I must regard as in all probability a portion of thisonce continuous system, hardened by metamorphic action,and which having, in consequence, resisted the denudingagencies that swept away the contemporary beds, still con-tinue to wrap over the contorted and broken gneisses andgranites of the district, and to form its most elevated moun-tains. It is the surviving fragment of a covering of whichalmost all the other portions have crumbled away piecemeal,and disappeared.