THE FRESH-WATER LOCHS OF SCOTLAND. 
167 
LOCHS OF THE NAIRN BASIN. 
The three lochs within the Nairn basin (see Index Map, Fig. 19) that 
were sounded by the Lake Survey are situated in Inverness-shire at the 
head of the river, over 20 miles to the south-west of the town of Nairn, 
and comparatively close to the eastern shore of Loch Ness, being, indeed, 
sandwiched between Lochs Ashie and Ruthven of the Ness basin. They 
form a connected series. Loch Ceo-GHas flowing into Loch Dim na Seil- 
cheig, the most important of the series, and thence into Loch a’ Chlachain. 
They all contain trout, and Loch Dim na Seilcheig also contains char, but 
the fishing in it is preserved. 
Loch Ceo-Glus (see Plate LXIV.) lies about 11 miles south of Inver- 
ness, and only a mile and a half from the eastern shore of Loch Ness, 
opposite Urquhart bay. Elongate in form, it trends in a south-west and 
north-east direction, and is nearly a mile in length, though the maximum 
breadth is only about one-seventh of a mile, the superficial area being 
about 54 acres. The northern portion of the loch is shallow, with the 
deeper water in the southern half, the maximum depth of 32 feet having 
been recorded little more than a quarter of a mile from the southern end, 
and towards the western shore, which is bordered by vertical and over- 
hanging clifts. The volume of water is estimated at 24 million cubic feet, 
and the mean depth at a little over 10 feet. Nearly two-thirds of the lake- 
floor is covered by less than 10 feet of water. The loch was surveyed on 
May 1, 1903, when the elevation was found to be 762‘9 feet above the sea, 
or a foot lower than the level observed by the Ordnance Survey officers on 
March 2<S, 1871. Temperatures taken in the deepest part of the loch 
showed that the water was nearly uniform in temperature from surface to 
bottom, the readings being : — 
Surface ... 
10 feet ... 
20 „ ... 
30 „ ... 
46°-3 Fahr. 
46°-2 „ 
46°*1 „ 
46°-0 „ 
Loch Dun na Seilcheig (see Plate LXIV.). — Loch Dim na Seilcheig 
(or Duntelchaig) is a large and deep loch lying about half a mile to 
the north-east of Loch Ceo-Glas, the difference in level being about 
60 feet. Somewhat irregular in outline and variable in width, the loch 
trends in a south-west and north-east direction, and is nearly 3J miles 
