ON THE NATURAL HISTORY OF THE SOUTH OF SCOTLAND. 231 



although less broken. In this ridge, which marks the limits of the counties of 

 Peebles and Dumfries, is distinguished the mountain of Hartfell, thegheight of 

 which is 2,635 feet. On its southern side is a singular ravine of great depth, 

 totally destitute of vegetation, and having its sides composed of black or dark 

 grey argillaceous slate and grey- wacke, in thin strata running from S. W. to N. E., 

 dipping to the west, and inclined at an angle of about 50°. The eastern side of 

 this ravine is composed of crumbled shale, beneath which is a fragmentary mass 

 containing much iron, and from which flow the celebrated chalybeate springs. 



This mountain and the others in its vicinity are for the most part covered with 

 spongy peat, and afford a rather luxuriant vegetation, consisting chiefly of Cal- 

 luna vulgaris, Erica cinerea, and the common Juncece and Cyperaceaz. At their 

 southern basis, the first rock that presents itself, in nearly horizontal strata, is a 

 dark-red friable sandstone, apparently of the new red series. Northward they 

 continue of their ordinary geological character, forming rounded masses, with long 

 narrow valleys, totally destitute of wood, and presenting only a few small Wil- 

 lows at long intervals along the clear streams which hasten to join the Tweed. 

 The only remarkable plant, besides the Saxifrages and some of the other species 

 mentioned above, that I observed in these valleys, is Cnicus heterophyllus, which 

 grows abundantly at Carterhope on the Frood. 



Descending the Tweed, we find it at first in all respects resembling its nume- 

 rous tributaries, flowing rapidly over a bed of pebbles, and nowhere presenting a 

 fall or even a rapid, excepting at the bridge near Tweedsmuir Church, where the 

 nearly vertical grey-wacke strata are exposed for a small space, leaving between 

 them a chasm in which the river flows deep and clear, and which bears a consi- 

 derable resemblance to the Linn of Dee in Braemar. At the mouth of the Frood 

 there is also a small waterfall or rapid, but in no other part of that stream is there 

 any appearance of turbulence. 



At Crook, on the left bank of the Tweed, and at the lower extremity of the 

 parish of Tweedsmuir, is a quarry of transition limestone, celebrated in the Hut- 

 tonian controversy, as affording an instance of organic remains contained in a 

 primitive district, the grey-wacke of these hills having been mistaken for granite. 

 And here it may be proper to state a fact which is not so generally^known, or at 

 least not so generally acknowledged, as it ought to be. The geological nature of 

 this great range of the southern division of Scotland was first determined by Pro- 

 fessor Jameson, after his return from Germany, to belong to the transition series, 

 and to present characters similar to those of the grey-wacke deposits of that coun- 

 try. Previous to that period, the transition rocks of England and Scotland were 

 not understood. 



If we follow the course of the river, through the parishes of Drumelzier and 

 Stobo, we find little variation in the scenery, the valley being merely somewhat 



