134 
BATHYMETRICAL SURVEY OF 
LOCHS OF THE TWEED BASIN 
The large area drained by the river Tweed (see Index Map, Fig. 15) 
is on the whole remarkably devoid of lochs. It is true there are a dozen 
little lochs on the borders of Eoxburghshire and Selkirkshire, drained by 
the Teviot branch of the Tweed, but they are very small, and were not 
sounded by the Lake Survey. The principal loch is the well-known 
St. Mary’s Loch, with the adjacent Loch of the Lowes, in Selkirkshire, on 
the Yarrow branch of the Tweed, while a notable addition has recently 
been made by the construction, for the supply of water to the city of 
Edinburgh and surrounding district, of the Talla reservoir in Peebles- 
shire, which lies about 6 miles west of St, Mary’s Loch, on the Talla 
branch of the Tweed. Of the three lochs surveyed, St. Mary’s Loch is the 
largest and the Loch of the Lowes the smallest, Talla reservoir being 
intermediate in point of size : — St. Mary’s Loch slightly exceeds 3 miles in 
length, Talla reservoir is nearly miles in length, while the Loch of the 
Lowes is less than a mile in length ; the superficial area of St. Mary’s 
