THE FRESH-WATER LOCHS OF SCOTLAND. 
53 
LOCHS OF THE TAY BASIN. 
Extent of the Tay Basin . — The whole area of the drainage basin of 
the Tay, including the estuary as far as a line joining Tents Muir Point 
with Monifieth, as measured with the planimeter on the 1-inch Ordnance 
Survey maps, is 2509-73 square miles.* Considerably more than one- 
fourth of this area drains directly into fresh-water lochs, of which there 
PIG. 14. INDEX MAP OP THE TAT BASIN. 
are seventy, including some of the largest in Scotland — Lochs Tay and 
Ericht, for instance, being over 14 miles in length, while eight of them 
exceed 2 miles in length. 
* Geikie {A 71 Elementary Geography oj the British Islands., London, 1888, p. 86) gives the 
drainage basin of the Tay as 2250 square miles and Lawson Geography of River Systems, 
London, N.D., p. 6) as 2400 [square] miles. According to Geikie, the Tay pours a larger 
volume of water into the sea than any other British river, and its drainage area is the largest 
in Scotland, and seventh in point of size in the British Islands, being exceeded by that of 
the Shannon in Ireland, the Thames, Severn, Ouse, Trent, and Gi'eat Ouse in England. 
