Igneous rocks of Teviot and Liddesdale

Abstract

Introduction. The district dealt with in the following pages forms a belt of country about fifteen miles in width. It extends from Roxburgh and Melrose in a south-easterly direction as far as Langholm and Canonbie Moor, and is included in Sheets 25, 17 and 11 of the Geological Survey's one-inch to a mile map of Scotland. It culminates in the elevated moorland watershed, just under 2000 feet in height, and is drained to the north by the Teviot Water System, whilst its southern slopes are segmented by the picturesque upper reaches of the Ewes, Hermitage and Liddel Waters. The most noteworthy features of the area are the steep cone-shaped peaks which stand out in sharp contrast to the rounded and flat-topped Silurian hills, or rise abruptly from the undulating plains near Jedburgh and Ancrum. These are the vents of Calciferous Sandstone volcanoes which have been exposed by great denudation, for not only have their own associated lavas been eroded away, but the removal has been effected also of a considerable thickness of the cementstone group and most of the underlying lavas of the plateaux series 1 which these volcanoes pierced. It was clearly shown by Dr Peach that the Calciferous Sandstone Series had a westward extension of ten miles or more beyond its present boundary. He found fragments of sandstone, fossiliferous limestone, and shale of Calciferous Sandstone age which had fallen into the funnels of these volcanoes, and had thus been preserved at great depths, helping