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, the height 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 CaU 
luna vulgaris^ Erica cinereal and the common Juncecs. and CyperacecE. 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 Cnicm heteropkyllus^ 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, dr 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, tha valley being merely somewhat 
