V.—On the Geology of Cockburnlaw, and the adjoining District, in Berwickshire; with a Map and Sections

Abstract

The portion of Berwickshire, of which the object of this paper is to describe the more remarkable geological features, comprises, within a very limited space, an assemblage of phenomena of the highest interest, in relation to the wonderful changes which this part of our island has undergone in the earlier periods of the earth's history. Its situation is immediately to the north of Dunse, and its area is about 16 square miles, within which are comprehended the junctions of the greywacke rocks of the Lammermuirs, with the strata of the old red sandstone formation, and of the latter with the lower members of the coal measures. The chief eminences within the district are Cockburnlaw, which attains a height of 912 feet above the level of the sea; Dunselaw, 630 feet; the Knock, Borthwick, and Castlemains Hills; and the Staneshiel, a hill of the same formation as Cockburnlaw, from which it is separated by a ravine of 300 or 400 feet deep, in which the Whiteadder flows. The general topographical features of the district will be best understood by reference to the accompanying map.

The Geology and Petrology of the Cockburn Law Intrusion, Berwickshire

“…The granite has itself been acted upon a little, as shown by the presence of tourmaline in the heavy mineral separations, but the action was very slight, since no tourmaline has been seen in any of the thin sections examined. Stevenson (1849) refers to galena and copper-pyrites which were found in the intrusion near the top of Stoneshiel Hill, and these minerals are probably products of pneumatolytic action.…”

“…This activity is difficult to trace, but copper lodes and mines are known to have existed, the evidence being place names on Ordnance Survey maps, which indicate the localities of some of the old copper mines. A mine is marked on the map published by Stevenson (1849) and in the text he refers to the occurrence of malachite. The original copper ore was probably associated with the late-stage activity accompanying the consolidation of the intrusion.…”

“…The first good description is given by Stevenson (1849), he noticed the variability of the granite and even at that early date attributed the " marginal ' syenites ' ( = diorites) to greywackes fused by the agency of the molten granite ". F. Walker in two papers (1925) and (1928) described the Cockburn Law intrusion together with other Southern Upland Intrusions.…”

Sedimentology and palaeogeography of the Upper Old Red Sandstone in the Scottish Border Basin

“…has received more attention. The historic discovery and interpretation of the basal unconformity by Hutton was followed by the work of Milne (1843), Stevenson (1845), Nicol (1855) and Duncan (1855). These workers collected characteristic Upper O.R.S.…”