XI.—Notes on the Geology of the Eildon Hills, in Roxburghshire

Abstract

The following remarks, being the result of a careful examination of a small district of country characteristic of the relations of the trap formations, are perhaps worthy of being recorded; although the general features of the county of Roxburgh have been very clearly stated in a paper by Mr Milne, published in the 15th volume of the Edinburgh Transactions.The outburst of porphyritic trap forming the conspicuous small group of the Eildon Hills, may be stated to be surrounded by the characteristic greywacke of the south of Scotland. It forms an elongated patch on the map, extending from the west end of Bowden Muir in the direction of the town of Selkirk, and running from west-south-west to east-north-east (true) towards Bemerside Hill, on the north bank of the Tweed. The breadth is variable, probably less than is generally supposed; but it cannot be accurately ascertained, owing to the accumulated diluvium which covers the whole south-eastern slope of this elevated ridge. On this account, my observations on the contact of rocks have been almost entirely confined to the northern and western boundaries of the trap, although the other side was examined with equal care.