BANKS OF THE TWEED AND SOME OF ITS TRIBUTARIES. 533 
feet, a lake may have been formed at a height of 180 or 185 feet above the sea- 
level, having its overflow at the north end, near Etal and Crookham, kept up 
by a blockage there, which was in time cut through. ~ 
(3.) The River Leader, at the town of Lauder, runs through a valley 
about 3 miles long and a mile wide. Thirlstane Castle stands on an elon- 
gated kaim of gravel, whose direction is parallel with the sides of the 
valley, and whose ridge is about 40 feet above the river. The position of 
Thirlstane Castle suggests, that the castle had been erected on the kaim for 
the sake of the protection afforded by the water which originally surrounded 
it. On the east side of the kaim, there was the river; and on the west side, a 
deep morass, across which a causeway afforded access to the castle. Between 
the town of Lauder and Whitslaid Castle (situated about 2 miles lower down 
the river), traces are visible of what had been the bottom of a lake from 35 to 
45 feet above the present bed of the river. After the lake had disappeared, 
the river cut its way through the beds of sand and gravel which formed the 
lake bottom—leaving sloping terraces on each side of the present valley, at 
different levels, still visible at several places. 
(4.) Many other places in the Border Counties might be named, where hori- 
zontal terraces occur, indicative of lakes long since drained or dried up. The 
small valley near Grant’s House, Berwickshire, through which the North British 
Railway passes, is an example. 
Thornton Loch, in Northumberland, was once a sheet of water a mile long ; 
it is now a green meadow, with banks on each side, betokening its lacu- 
strine origin. Several old camps* and peels had been erected near it, for the 
protection it afforded. 
Primside Loch, in Roxburghshire, is the only one which remains of a series 
of lakes which had occupied the valleys between Kirknewton and More- 
battle. 
The former existence of lakes and marshes in Berwickshire is also indicated 
by such names as “ Billie-myre,” ‘“ Drake-myre,” “ Dunse Common Myre,” and 
by the general name of “ Merse,” applicable to the county. 
In Roxburghshire, such names as “ Mer-ton,” “ Mer-wich,” “ Black- 
myre,” “Myre-dyke,” ‘“More-battle” (originally ‘Mere-bottel”), afford like 
evidence. 
6. In the foregomg part of this paper, a description has been given of 
terraces and cliffs, connected with the River Tweed and its tributaries. But 
in other parts of the general valley of the Tweed, there are terraces and cliffs, 
in some respects similar, but probably having a different origin. 
* In Eccles parish, at Hardacres, there is an old camp, on the west end of a kaim or high gravel 
ridge, which had been surrounded by water on three sides. Swinton Loch is also spoken of, in “ Boston’s 
Memoirs.” There is not even a marsh there now. 
VOL. XXVII. PART IV. 7B 
