650 FOURTH REPORT — 1834. 



Account of the central Portion of the great Mountain Range 

 of the South of Scotland, in which arise the Sources of the 

 Tweed. By W. Macgillivray. 



The mountains forming the most elevated part of this range are 

 situated in the parishes of Tweedsmuir, Megget, and Mannor, 

 which form the southern and south-eastern parts of the inland 

 county of Peebles, and are continuous with the high land form- 

 ing the celebrated pastoral districts of Yarrow and Ettrick in 

 Selkirkshire, and with the higher parts of the parish of Moffat in 

 Dumfries. The region is composed of miiform, smooth, round- 

 ed hills of grauwacke, scarcely ever precipitous or even abrupt, 

 clothed to the summits with Juncece, Cyperacece, grasses, heath, 

 and pasture plants, and separated into groups or ridges by long, 

 narrow, straight valleys, which, although generally green, sel- 

 dom present any natural wood, even along the clear streams that 

 flow into the valley of the Tweed. Whitecoon, Hartfell, and 

 other mountains, were described, and the alpine plants observed 

 on them enumerated, with the view of contrasting this region 

 with the Grampian range. An account was also given of the 

 vegetation of the clenchs or ravines. The Tweed was then fol- 

 lowed from its sources to Peebles, and finally to the mouths 

 of the Gala and Ettrick, in the whole of which space the rocks 

 are composed of gramvacke, grauwacke-slate, clay-slate, slate- 

 clay, and occasional small beds of limestone, none of which, 

 however, are wrought. The districts of Yarrow and Ettrick, 

 which are of precisely similar geological structure, were then 

 described, with reference to their scenery, vegetation, and ani- 

 mal productions. 



Perhaps few districts in Scotland, of equal extent, present less 

 varied geological phsenomena than that which contains the 

 sources of the Tweed. The general direction of the strata is 

 from south-west to north-east; they ai-e usually highly inclined, 

 but present everj' degree of inclination : the general dip is to 

 the north-west. The composition of the grauwacke exhibits 

 considerable variety. 



In form, the hUls approximate in a considerable degi'ee to 

 many of the granite masses of Aberdeenshire, but they never 

 present the precipices and corries, which characterize the more 

 elevated of the latter. The whole district, with its rounded, 

 smooth, sloped mountains, connected in elongated heaps, its 

 long, narroAv, straight, or slightly tortuous valleys, its argilla- 

 ceous and pebbly soil, its clear and rapid streams, and its grassy 

 vegetation, with the absence of natural and the scarceness of 



