THE FRESH-WATER LOCHS OF SCOTLAND. 
13 
in greatest width. At the upper end of the loch, where the river 
Balvag enters, there is a long spit formed of detritus brought down by 
the river, and this end of the loch for a distance of three-quarters of a 
mile is very shallow, while at the lower end the 50-feet contour is 
found within 200 yards of the outlet. The area between the 50-feet 
and 100-feet contours is estimated at about 162 acres, or 26 per cent, of 
the total area of the loch, while the area with depths under 50 feet is 
estimated at about 397 acres, or 65 per cent, of the area of the loch. 
When the loch was visited on April 6, 1899, it appeared from marks 
on the shore that the water had lately been 4 feet 10 inches higher than 
at that time, and it has been known to have been 12 or 18 inches lower, 
so that the rise and fall is about 6 feet in all. On one occasion a disc 
was visible down to a depth of 174 feet, and on another down to 20J feet. 
On the western shore, between IJ and IJ miles from the southern 
end of the loch, there is a remarkable sandy spit, which stretches out 
towards the centre of the loch, the origin of which appears to us some- 
what puzzling (see the Geological Notes by Messrs. Peach and Horne). 
67m /z- (see Plate VIII.).- — There are two lochs in Perthshire bear- 
ing this name, the one a little loch in the parish of Blair Atholl. The 
Loch Chon now under consideration lies to the south of Loch Katrine, 
and trends in a north-west and south-east direction. It lies at a height 
of 296 feet above sea-level, and the river into which it flows expands, a 
little distance to the south-east, into the small loch, Lochan Dubh or 
Loch Dhu, the surface of which is 10 feet lower. Loch Chon is over 
1| miles in length, and the greatest width is about one-third of a mile. 
The mean breadth, obtained by dividing the area of The loch by its 
length, is a quarter of a mile, being 15 per cent, of the length. Its 
waters cover an area of about 277 acres, or less than half a square mile, 
and it drains an area about 144 times greater, or nearly 4000 acres 
(nearly 6^ square miles). The number of soundings taken in Loch Chon 
was 157, the greatest depth observed being 75 feet. The mass of water 
contained in the loch is estimated at 358,000,000 cubic feet, and the 
mean depth at over’ 29 feet, or 39 per cent, of the maximum depth. The 
length of the loch is 120 times the maximum depth, and 305 times the 
mean depth. 
Loch Chon is irregular in outline, and the contour-lines are also 
irregular. The deepest part of the loch {i.e. exceeding 50 feet) forms a 
long, narrow depression, situated approximately in the centre of the 
loch, but closer to the western than to the eastern shore, about seven- 
twelfths of a mile in length, with a maximum width of over one-sixth of 
a mile. The maximum depth, 75 feet, was found comparatively very 
close to the western shore, being in fact only about 130 yards distant ; 
this gives a slope of almost 1 in 5, and a similar steep slope is indicated 
by the near approach to the shore of the contour-lines for a considerable 
